From 4a6b001b89cbb646125a7bf6b11720b069d65d76 Mon Sep 17 00:00:00 2001
From: tarrinneal <tarrinneal@gmail.com>
Date: Fri, 27 Oct 2023 10:46:26 -0700
Subject: [PATCH 1/5] space

---
 .../example/app/ios/Runner/Messages.g.swift   |   4 +-
 packages/pigeon/lib/swift_generator.dart      |   4 +-
 .../ios/Classes/CoreTests.gen.swift           | 104 +++++++++---------
 .../macos/Classes/CoreTests.gen.swift         | 104 +++++++++---------
 4 files changed, 108 insertions(+), 108 deletions(-)

diff --git a/packages/pigeon/example/app/ios/Runner/Messages.g.swift b/packages/pigeon/example/app/ios/Runner/Messages.g.swift
index ef38ee5849c..ae45905a758 100644
--- a/packages/pigeon/example/app/ios/Runner/Messages.g.swift
+++ b/packages/pigeon/example/app/ios/Runner/Messages.g.swift
@@ -175,14 +175,14 @@ class ExampleHostApiSetup {
 }
 /// Generated protocol from Pigeon that represents Flutter messages that can be called from Swift.
 protocol MessageFlutterApiProtocol {
-  func flutterMethod(aString aStringArg: String?, completion: @escaping (Result<String, FlutterError>) -> Void) 
+  func flutterMethod(aString aStringArg: String?, completion: @escaping (Result<String, FlutterError>) -> Void)
 }
 class MessageFlutterApi: MessageFlutterApiProtocol {
   private let binaryMessenger: FlutterBinaryMessenger
   init(binaryMessenger: FlutterBinaryMessenger){
     self.binaryMessenger = binaryMessenger
   }
-  func flutterMethod(aString aStringArg: String?, completion: @escaping (Result<String, FlutterError>) -> Void)  {
+  func flutterMethod(aString aStringArg: String?, completion: @escaping (Result<String, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_example_package.MessageFlutterApi.flutterMethod", binaryMessenger: binaryMessenger)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
diff --git a/packages/pigeon/lib/swift_generator.dart b/packages/pigeon/lib/swift_generator.dart
index af96efd0205..762b318c067 100644
--- a/packages/pigeon/lib/swift_generator.dart
+++ b/packages/pigeon/lib/swift_generator.dart
@@ -882,7 +882,7 @@ String _getMethodSignature(Method func) {
       : _nullsafeSwiftTypeForDartType(func.returnType);
 
   if (func.arguments.isEmpty) {
-    return 'func ${func.name}(completion: @escaping (Result<$returnType, FlutterError>) -> Void) ';
+    return 'func ${func.name}(completion: @escaping (Result<$returnType, FlutterError>) -> Void)';
   } else {
     final Iterable<String> argTypes = func.arguments
         .map((NamedType e) => _nullsafeSwiftTypeForDartType(e.type));
@@ -895,7 +895,7 @@ String _getMethodSignature(Method func) {
     final String argsSignature = map3(argTypes, argLabels, argNames,
             (String type, String label, String name) => '$label $name: $type')
         .join(', ');
-    return 'func ${components.name}($argsSignature, completion: @escaping (Result<$returnType, FlutterError>) -> Void) ';
+    return 'func ${components.name}($argsSignature, completion: @escaping (Result<$returnType, FlutterError>) -> Void)';
   }
 }
 
diff --git a/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift b/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift
index 8b83e3d1771..3beab718895 100644
--- a/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift
+++ b/packages/pigeon/platform_tests/test_plugin/ios/Classes/CoreTests.gen.swift
@@ -1743,56 +1743,56 @@ class FlutterIntegrationCoreApiCodec: FlutterStandardMessageCodec {
 protocol FlutterIntegrationCoreApiProtocol {
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic calling.
-  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void) 
+  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void)
   /// Responds with an error from an async function returning a value.
-  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void) 
+  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void)
   /// Responds with an error from an async void function.
-  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void) 
+  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void)
   /// Returns the passed object, to test serialization and deserialization.
-  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void) 
+  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void)
   /// Returns the passed object, to test serialization and deserialization.
-  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void) 
+  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void)
   /// Returns passed in arguments of multiple types.
   ///
   /// Tests multiple-arity FlutterApi handling.
-  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void) 
+  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void)
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void) 
+  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void)
   /// Returns the passed int, to test serialization and deserialization.
-  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void) 
+  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void)
   /// Returns the passed double, to test serialization and deserialization.
-  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void) 
+  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void)
   /// Returns the passed string, to test serialization and deserialization.
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) 
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void) 
+  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void)
   /// Returns the passed list, to test serialization and deserialization.
-  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void) 
+  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void)
   /// Returns the passed map, to test serialization and deserialization.
-  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void) 
+  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void)
   /// Returns the passed enum to test serialization and deserialization.
-  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void) 
+  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void)
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void) 
+  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void)
   /// Returns the passed int, to test serialization and deserialization.
-  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void) 
+  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void)
   /// Returns the passed double, to test serialization and deserialization.
-  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void) 
+  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void)
   /// Returns the passed string, to test serialization and deserialization.
-  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void) 
+  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void)
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void) 
+  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void)
   /// Returns the passed list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void) 
+  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void)
   /// Returns the passed map, to test serialization and deserialization.
-  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void) 
+  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void)
   /// Returns the passed enum to test serialization and deserialization.
-  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void) 
+  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void)
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic asynchronous calling.
-  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void) 
+  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void)
   /// Returns the passed in generic Object asynchronously.
-  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) 
+  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)
 }
 class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   private let binaryMessenger: FlutterBinaryMessenger
@@ -1804,14 +1804,14 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   }
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic calling.
-  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void)  {
+  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noop", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { _ in
       completion(.success(Void()))
     }
   }
   /// Responds with an error from an async function returning a value.
-  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void)  {
+  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.throwError", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1830,14 +1830,14 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Responds with an error from an async void function.
-  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void)  {
+  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.throwErrorFromVoid", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { _ in
       completion(.success(Void()))
     }
   }
   /// Returns the passed object, to test serialization and deserialization.
-  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void)  {
+  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoAllTypes", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([everythingArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1858,7 +1858,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed object, to test serialization and deserialization.
-  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void)  {
+  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoAllNullableTypes", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([everythingArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1879,7 +1879,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   /// Returns passed in arguments of multiple types.
   ///
   /// Tests multiple-arity FlutterApi handling.
-  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void)  {
+  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.sendMultipleNullableTypes", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aNullableBoolArg, aNullableIntArg, aNullableStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1900,7 +1900,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void)  {
+  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoBool", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aBoolArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1921,7 +1921,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed int, to test serialization and deserialization.
-  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void)  {
+  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoInt", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anIntArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1942,7 +1942,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed double, to test serialization and deserialization.
-  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void)  {
+  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoDouble", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aDoubleArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1963,7 +1963,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed string, to test serialization and deserialization.
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)  {
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1984,7 +1984,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void)  {
+  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoUint8List", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2005,7 +2005,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed list, to test serialization and deserialization.
-  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void)  {
+  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoList", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2026,7 +2026,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed map, to test serialization and deserialization.
-  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void)  {
+  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoMap", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aMapArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2047,7 +2047,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed enum to test serialization and deserialization.
-  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void)  {
+  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoEnum", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anEnumArg.rawValue] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2068,7 +2068,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void)  {
+  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableBool", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aBoolArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2087,7 +2087,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed int, to test serialization and deserialization.
-  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void)  {
+  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableInt", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anIntArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2106,7 +2106,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed double, to test serialization and deserialization.
-  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void)  {
+  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableDouble", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aDoubleArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2125,7 +2125,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed string, to test serialization and deserialization.
-  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void)  {
+  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2144,7 +2144,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void)  {
+  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableUint8List", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2163,7 +2163,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void)  {
+  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableList", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2182,7 +2182,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed map, to test serialization and deserialization.
-  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void)  {
+  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableMap", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aMapArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2201,7 +2201,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed enum to test serialization and deserialization.
-  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void)  {
+  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableEnum", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anEnumArg?.rawValue] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2221,14 +2221,14 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   }
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic asynchronous calling.
-  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void)  {
+  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noopAsync", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { _ in
       completion(.success(Void()))
     }
   }
   /// Returns the passed in generic Object asynchronously.
-  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)  {
+  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoAsyncString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2363,8 +2363,8 @@ class FlutterSmallApiCodec: FlutterStandardMessageCodec {
 ///
 /// Generated protocol from Pigeon that represents Flutter messages that can be called from Swift.
 protocol FlutterSmallApiProtocol {
-  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void) 
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) 
+  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void)
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)
 }
 class FlutterSmallApi: FlutterSmallApiProtocol {
   private let binaryMessenger: FlutterBinaryMessenger
@@ -2374,7 +2374,7 @@ class FlutterSmallApi: FlutterSmallApiProtocol {
   var codec: FlutterStandardMessageCodec {
     return FlutterSmallApiCodec.shared
   }
-  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void)  {
+  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterSmallApi.echoWrappedList", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([msgArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2394,7 +2394,7 @@ class FlutterSmallApi: FlutterSmallApiProtocol {
       }
     }
   }
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)  {
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterSmallApi.echoString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
diff --git a/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift b/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift
index 8b83e3d1771..3beab718895 100644
--- a/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift
+++ b/packages/pigeon/platform_tests/test_plugin/macos/Classes/CoreTests.gen.swift
@@ -1743,56 +1743,56 @@ class FlutterIntegrationCoreApiCodec: FlutterStandardMessageCodec {
 protocol FlutterIntegrationCoreApiProtocol {
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic calling.
-  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void) 
+  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void)
   /// Responds with an error from an async function returning a value.
-  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void) 
+  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void)
   /// Responds with an error from an async void function.
-  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void) 
+  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void)
   /// Returns the passed object, to test serialization and deserialization.
-  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void) 
+  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void)
   /// Returns the passed object, to test serialization and deserialization.
-  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void) 
+  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void)
   /// Returns passed in arguments of multiple types.
   ///
   /// Tests multiple-arity FlutterApi handling.
-  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void) 
+  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void)
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void) 
+  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void)
   /// Returns the passed int, to test serialization and deserialization.
-  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void) 
+  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void)
   /// Returns the passed double, to test serialization and deserialization.
-  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void) 
+  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void)
   /// Returns the passed string, to test serialization and deserialization.
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) 
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void) 
+  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void)
   /// Returns the passed list, to test serialization and deserialization.
-  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void) 
+  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void)
   /// Returns the passed map, to test serialization and deserialization.
-  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void) 
+  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void)
   /// Returns the passed enum to test serialization and deserialization.
-  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void) 
+  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void)
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void) 
+  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void)
   /// Returns the passed int, to test serialization and deserialization.
-  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void) 
+  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void)
   /// Returns the passed double, to test serialization and deserialization.
-  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void) 
+  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void)
   /// Returns the passed string, to test serialization and deserialization.
-  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void) 
+  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void)
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void) 
+  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void)
   /// Returns the passed list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void) 
+  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void)
   /// Returns the passed map, to test serialization and deserialization.
-  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void) 
+  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void)
   /// Returns the passed enum to test serialization and deserialization.
-  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void) 
+  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void)
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic asynchronous calling.
-  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void) 
+  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void)
   /// Returns the passed in generic Object asynchronously.
-  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) 
+  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)
 }
 class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   private let binaryMessenger: FlutterBinaryMessenger
@@ -1804,14 +1804,14 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   }
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic calling.
-  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void)  {
+  func noop(completion: @escaping (Result<Void, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noop", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { _ in
       completion(.success(Void()))
     }
   }
   /// Responds with an error from an async function returning a value.
-  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void)  {
+  func throwError(completion: @escaping (Result<Any?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.throwError", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1830,14 +1830,14 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Responds with an error from an async void function.
-  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void)  {
+  func throwErrorFromVoid(completion: @escaping (Result<Void, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.throwErrorFromVoid", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { _ in
       completion(.success(Void()))
     }
   }
   /// Returns the passed object, to test serialization and deserialization.
-  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void)  {
+  func echo(_ everythingArg: AllTypes, completion: @escaping (Result<AllTypes, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoAllTypes", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([everythingArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1858,7 +1858,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed object, to test serialization and deserialization.
-  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void)  {
+  func echoNullable(_ everythingArg: AllNullableTypes?, completion: @escaping (Result<AllNullableTypes?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoAllNullableTypes", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([everythingArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1879,7 +1879,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   /// Returns passed in arguments of multiple types.
   ///
   /// Tests multiple-arity FlutterApi handling.
-  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void)  {
+  func sendMultipleNullableTypes(aBool aNullableBoolArg: Bool?, anInt aNullableIntArg: Int64?, aString aNullableStringArg: String?, completion: @escaping (Result<AllNullableTypes, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.sendMultipleNullableTypes", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aNullableBoolArg, aNullableIntArg, aNullableStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1900,7 +1900,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void)  {
+  func echo(_ aBoolArg: Bool, completion: @escaping (Result<Bool, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoBool", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aBoolArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1921,7 +1921,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed int, to test serialization and deserialization.
-  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void)  {
+  func echo(_ anIntArg: Int64, completion: @escaping (Result<Int64, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoInt", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anIntArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1942,7 +1942,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed double, to test serialization and deserialization.
-  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void)  {
+  func echo(_ aDoubleArg: Double, completion: @escaping (Result<Double, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoDouble", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aDoubleArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1963,7 +1963,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed string, to test serialization and deserialization.
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)  {
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -1984,7 +1984,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void)  {
+  func echo(_ aListArg: FlutterStandardTypedData, completion: @escaping (Result<FlutterStandardTypedData, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoUint8List", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2005,7 +2005,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed list, to test serialization and deserialization.
-  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void)  {
+  func echo(_ aListArg: [Any?], completion: @escaping (Result<[Any?], FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoList", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2026,7 +2026,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed map, to test serialization and deserialization.
-  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void)  {
+  func echo(_ aMapArg: [String?: Any?], completion: @escaping (Result<[String?: Any?], FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoMap", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aMapArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2047,7 +2047,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed enum to test serialization and deserialization.
-  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void)  {
+  func echo(_ anEnumArg: AnEnum, completion: @escaping (Result<AnEnum, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoEnum", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anEnumArg.rawValue] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2068,7 +2068,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed boolean, to test serialization and deserialization.
-  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void)  {
+  func echoNullable(_ aBoolArg: Bool?, completion: @escaping (Result<Bool?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableBool", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aBoolArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2087,7 +2087,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed int, to test serialization and deserialization.
-  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void)  {
+  func echoNullable(_ anIntArg: Int64?, completion: @escaping (Result<Int64?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableInt", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anIntArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2106,7 +2106,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed double, to test serialization and deserialization.
-  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void)  {
+  func echoNullable(_ aDoubleArg: Double?, completion: @escaping (Result<Double?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableDouble", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aDoubleArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2125,7 +2125,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed string, to test serialization and deserialization.
-  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void)  {
+  func echoNullable(_ aStringArg: String?, completion: @escaping (Result<String?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2144,7 +2144,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed byte list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void)  {
+  func echoNullable(_ aListArg: FlutterStandardTypedData?, completion: @escaping (Result<FlutterStandardTypedData?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableUint8List", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2163,7 +2163,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed list, to test serialization and deserialization.
-  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void)  {
+  func echoNullable(_ aListArg: [Any?]?, completion: @escaping (Result<[Any?]?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableList", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aListArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2182,7 +2182,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed map, to test serialization and deserialization.
-  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void)  {
+  func echoNullable(_ aMapArg: [String?: Any?]?, completion: @escaping (Result<[String?: Any?]?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableMap", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aMapArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2201,7 +2201,7 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
     }
   }
   /// Returns the passed enum to test serialization and deserialization.
-  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void)  {
+  func echoNullable(_ anEnumArg: AnEnum?, completion: @escaping (Result<AnEnum?, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoNullableEnum", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([anEnumArg?.rawValue] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2221,14 +2221,14 @@ class FlutterIntegrationCoreApi: FlutterIntegrationCoreApiProtocol {
   }
   /// A no-op function taking no arguments and returning no value, to sanity
   /// test basic asynchronous calling.
-  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void)  {
+  func noopAsync(completion: @escaping (Result<Void, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noopAsync", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage(nil) { _ in
       completion(.success(Void()))
     }
   }
   /// Returns the passed in generic Object asynchronously.
-  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)  {
+  func echoAsync(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.echoAsyncString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2363,8 +2363,8 @@ class FlutterSmallApiCodec: FlutterStandardMessageCodec {
 ///
 /// Generated protocol from Pigeon that represents Flutter messages that can be called from Swift.
 protocol FlutterSmallApiProtocol {
-  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void) 
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) 
+  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void)
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)
 }
 class FlutterSmallApi: FlutterSmallApiProtocol {
   private let binaryMessenger: FlutterBinaryMessenger
@@ -2374,7 +2374,7 @@ class FlutterSmallApi: FlutterSmallApiProtocol {
   var codec: FlutterStandardMessageCodec {
     return FlutterSmallApiCodec.shared
   }
-  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void)  {
+  func echo(_ msgArg: TestMessage, completion: @escaping (Result<TestMessage, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterSmallApi.echoWrappedList", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([msgArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {
@@ -2394,7 +2394,7 @@ class FlutterSmallApi: FlutterSmallApiProtocol {
       }
     }
   }
-  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void)  {
+  func echo(_ aStringArg: String, completion: @escaping (Result<String, FlutterError>) -> Void) {
     let channel = FlutterBasicMessageChannel(name: "dev.flutter.pigeon.pigeon_integration_tests.FlutterSmallApi.echoString", binaryMessenger: binaryMessenger, codec: codec)
     channel.sendMessage([aStringArg] as [Any?]) { response in
       guard let listResponse = response as? [Any?] else {

From 3645bcc741ee4ea2c2ca01f1045ff4b0fe719dd1 Mon Sep 17 00:00:00 2001
From: tarrinneal <tarrinneal@gmail.com>
Date: Tue, 2 Jan 2024 16:09:24 -0800
Subject: [PATCH 2/5] fix java void return type

---
 packages/pigeon/lib/java_generator.dart       | 12 +++++--
 .../AlternateLanguageTestPlugin.java          |  8 ++---
 .../CoreTests.java                            | 36 +++++++++----------
 .../AsyncTest.java                            |  4 +--
 packages/pigeon/test/java_generator_test.dart |  4 +--
 5 files changed, 35 insertions(+), 29 deletions(-)

diff --git a/packages/pigeon/lib/java_generator.dart b/packages/pigeon/lib/java_generator.dart
index 55866c7d59d..27c5a258187 100644
--- a/packages/pigeon/lib/java_generator.dart
+++ b/packages/pigeon/lib/java_generator.dart
@@ -449,7 +449,9 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
 
       for (final Method func in api.methods) {
         final String resultType =
-            func.returnType.isNullable ? 'NullableResult' : 'Result';
+            func.returnType.isNullable || func.returnType.isVoid
+                ? 'NullableResult'
+                : 'Result';
         final String returnType = func.returnType.isVoid
             ? 'Void'
             : _javaTypeForDartType(func.returnType);
@@ -634,7 +636,9 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
   void _writeInterfaceMethod(JavaOptions generatorOptions, Root root,
       Indent indent, Api api, final Method method) {
     final String resultType =
-        method.returnType.isNullable ? 'NullableResult' : 'Result';
+        method.returnType.isNullable || method.returnType.isVoid
+            ? 'NullableResult'
+            : 'Result';
     final String nullableType = method.isAsynchronous
         ? ''
         : _nullabilityAnnotationFromType(method.returnType);
@@ -749,7 +753,9 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
                     : '.index';
               }
               final String resultType =
-                  method.returnType.isNullable ? 'NullableResult' : 'Result';
+                  method.returnType.isNullable || method.returnType.isVoid
+                      ? 'NullableResult'
+                      : 'Result';
               const String resultName = 'resultCallback';
               indent.format('''
 $resultType<$returnType> $resultName =
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java
index 21037c5e99c..cc9ffe0ff14 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java
@@ -208,7 +208,7 @@ public void throwErrorFromVoid() {
   }
 
   @Override
-  public void noopAsync(@NonNull Result<Void> result) {
+  public void noopAsync(@NonNull NullableResult<Void> result) {
     result.success(null);
   }
 
@@ -218,7 +218,7 @@ public void throwAsyncError(@NonNull NullableResult<Object> result) {
   }
 
   @Override
-  public void throwAsyncErrorFromVoid(@NonNull Result<Void> result) {
+  public void throwAsyncErrorFromVoid(@NonNull NullableResult<Void> result) {
     result.error(new RuntimeException("An error"));
   }
 
@@ -338,7 +338,7 @@ public void echoAsyncNullableEnum(
   }
 
   @Override
-  public void callFlutterNoop(@NonNull Result<Void> result) {
+  public void callFlutterNoop(@NonNull NullableResult<Void> result) {
     flutterApi.noop(result);
   }
 
@@ -348,7 +348,7 @@ public void callFlutterThrowError(@NonNull NullableResult<Object> result) {
   }
 
   @Override
-  public void callFlutterThrowErrorFromVoid(@NonNull Result<Void> result) {
+  public void callFlutterThrowErrorFromVoid(@NonNull NullableResult<Void> result) {
     flutterApi.throwErrorFromVoid(result);
   }
 
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
index b6a72835e4a..fae6d3d289b 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
@@ -1139,7 +1139,7 @@ AllNullableTypes sendMultipleNullableTypes(
      * A no-op function taking no arguments and returning no value, to sanity test basic
      * asynchronous calling.
      */
-    void noopAsync(@NonNull Result<Void> result);
+    void noopAsync(@NonNull NullableResult<Void> result);
     /** Returns passed in int asynchronously. */
     void echoAsyncInt(@NonNull Long anInt, @NonNull Result<Long> result);
     /** Returns passed in double asynchronously. */
@@ -1162,7 +1162,7 @@ void echoAsyncMap(
     /** Responds with an error from an async function returning a value. */
     void throwAsyncError(@NonNull NullableResult<Object> result);
     /** Responds with an error from an async void function. */
-    void throwAsyncErrorFromVoid(@NonNull Result<Void> result);
+    void throwAsyncErrorFromVoid(@NonNull NullableResult<Void> result);
     /** Responds with a Flutter error from an async function returning a value. */
     void throwAsyncFlutterError(@NonNull NullableResult<Object> result);
     /** Returns the passed object, to test async serialization and deserialization. */
@@ -1192,11 +1192,11 @@ void echoAsyncNullableMap(
     /** Returns the passed enum, to test asynchronous serialization and deserialization. */
     void echoAsyncNullableEnum(@Nullable AnEnum anEnum, @NonNull NullableResult<AnEnum> result);
 
-    void callFlutterNoop(@NonNull Result<Void> result);
+    void callFlutterNoop(@NonNull NullableResult<Void> result);
 
     void callFlutterThrowError(@NonNull NullableResult<Object> result);
 
-    void callFlutterThrowErrorFromVoid(@NonNull Result<Void> result);
+    void callFlutterThrowErrorFromVoid(@NonNull NullableResult<Void> result);
 
     void callFlutterEchoAllTypes(@NonNull AllTypes everything, @NonNull Result<AllTypes> result);
 
@@ -2097,8 +2097,8 @@ static void setUp(
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                Result<Void> resultCallback =
-                    new Result<Void>() {
+                NullableResult<Void> resultCallback =
+                    new NullableResult<Void>() {
                       public void success(Void result) {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
@@ -2434,8 +2434,8 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                Result<Void> resultCallback =
-                    new Result<Void>() {
+                NullableResult<Void> resultCallback =
+                    new NullableResult<Void>() {
                       public void success(Void result) {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
@@ -2834,8 +2834,8 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                Result<Void> resultCallback =
-                    new Result<Void>() {
+                NullableResult<Void> resultCallback =
+                    new NullableResult<Void>() {
                       public void success(Void result) {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
@@ -2892,8 +2892,8 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                Result<Void> resultCallback =
-                    new Result<Void>() {
+                NullableResult<Void> resultCallback =
+                    new NullableResult<Void>() {
                       public void success(Void result) {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
@@ -3574,7 +3574,7 @@ public FlutterIntegrationCoreApi(@NonNull BinaryMessenger argBinaryMessenger) {
     /**
      * A no-op function taking no arguments and returning no value, to sanity test basic calling.
      */
-    public void noop(@NonNull Result<Void> result) {
+    public void noop(@NonNull NullableResult<Void> result) {
       final String channelName =
           "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noop";
       BasicMessageChannel<Object> channel =
@@ -3626,7 +3626,7 @@ public void throwError(@NonNull NullableResult<Object> result) {
           });
     }
     /** Responds with an error from an async void function. */
-    public void throwErrorFromVoid(@NonNull Result<Void> result) {
+    public void throwErrorFromVoid(@NonNull NullableResult<Void> result) {
       final String channelName =
           "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.throwErrorFromVoid";
       BasicMessageChannel<Object> channel =
@@ -4251,7 +4251,7 @@ public void echoNullableEnum(
      * A no-op function taking no arguments and returning no value, to sanity test basic
      * asynchronous calling.
      */
-    public void noopAsync(@NonNull Result<Void> result) {
+    public void noopAsync(@NonNull NullableResult<Void> result) {
       final String channelName =
           "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noopAsync";
       BasicMessageChannel<Object> channel =
@@ -4358,7 +4358,7 @@ public interface HostSmallApi {
 
     void echo(@NonNull String aString, @NonNull Result<String> result);
 
-    void voidVoid(@NonNull Result<Void> result);
+    void voidVoid(@NonNull NullableResult<Void> result);
 
     /** The codec used by HostSmallApi. */
     static @NonNull MessageCodec<Object> getCodec() {
@@ -4407,8 +4407,8 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                Result<Void> resultCallback =
-                    new Result<Void>() {
+                NullableResult<Void> resultCallback =
+                    new NullableResult<Void>() {
                       public void success(Void result) {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java
index 3eefea01e9d..819b2b37487 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java
@@ -24,7 +24,7 @@ public void echo(@NonNull String value, Result<String> result) {
     }
 
     @Override
-    public void voidVoid(Result<Void> result) {
+    public void voidVoid(NullableResult<Void> result) {
       result.success(null);
     }
   }
@@ -36,7 +36,7 @@ public void echo(@NonNull String value, Result<String> result) {
     }
 
     @Override
-    public void voidVoid(Result<Void> result) {
+    public void voidVoid(NullableResult<Void> result) {
       result.error(new Exception("error"));
     }
   }
diff --git a/packages/pigeon/test/java_generator_test.dart b/packages/pigeon/test/java_generator_test.dart
index 1cae5f664a5..3754d3f2b04 100644
--- a/packages/pigeon/test/java_generator_test.dart
+++ b/packages/pigeon/test/java_generator_test.dart
@@ -397,7 +397,7 @@ void main() {
     expect(
         code,
         contains(
-            'public void doSomething(@NonNull Input arg0Arg, @NonNull Result<Void> result)'));
+            'public void doSomething(@NonNull Input arg0Arg, @NonNull NullableResult<Void> result)'));
     expect(code, contains('result.success(null);'));
   });
 
@@ -1307,7 +1307,7 @@ void main() {
     expect(
         code,
         contains(
-            'public void doit(@Nullable Long fooArg, @NonNull Result<Void> result) {'));
+            'public void doit(@Nullable Long fooArg, @NonNull NullableResult<Void> result) {'));
   });
 
   test('background platform channel', () {

From 87147c25b616215b9f0421d017118f51cefa3ebe Mon Sep 17 00:00:00 2001
From: tarrinneal <tarrinneal@gmail.com>
Date: Tue, 2 Jan 2024 16:12:52 -0800
Subject: [PATCH 3/5] changelog

---
 packages/pigeon/CHANGELOG.md             | 4 ++++
 packages/pigeon/lib/generator_tools.dart | 2 +-
 packages/pigeon/pubspec.yaml             | 2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index 54a50c319ef..932f2fca60d 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 15.0.3
+
+* [java] Fixes `Void` result type bug.
+
 ## 15.0.2
 
 * Prevents optional and non-positional parameters in Flutter APIs.
diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
index a510b55bd74..fcf255bb8bf 100644
--- a/packages/pigeon/lib/generator_tools.dart
+++ b/packages/pigeon/lib/generator_tools.dart
@@ -13,7 +13,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '15.0.2';
+const String pigeonVersion = '15.0.3';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index 67f7fa73e69..09b82181453 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 15.0.2 # This must match the version in lib/generator_tools.dart
+version: 15.0.3 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: ">=3.0.0 <4.0.0"

From 59010883425736479c1891e496dd889ca0351f15 Mon Sep 17 00:00:00 2001
From: tarrinneal <tarrinneal@gmail.com>
Date: Wed, 3 Jan 2024 21:10:28 -0800
Subject: [PATCH 4/5] VoidResult

---
 packages/pigeon/CHANGELOG.md                  |  6 +-
 packages/pigeon/lib/generator_tools.dart      |  2 +-
 packages/pigeon/lib/java_generator.dart       | 64 ++++++++++++-------
 .../AlternateLanguageTestPlugin.java          | 11 ++--
 .../CoreTests.java                            | 60 +++++++++--------
 .../AsyncTest.java                            |  6 +-
 packages/pigeon/pubspec.yaml                  |  2 +-
 packages/pigeon/test/java_generator_test.dart |  6 +-
 8 files changed, 92 insertions(+), 65 deletions(-)

diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index 932f2fca60d..dd717d8d9f0 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,6 +1,8 @@
-## 15.0.3
+## 16.0.0
+
+* [java] Adds `VoidResult` type for `Void` returns.
+* **Breaking Change** [java] Updates all `Void` return types to use new `VoidResult`.
 
-* [java] Fixes `Void` result type bug.
 
 ## 15.0.2
 
diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
index fcf255bb8bf..ba32f720a2a 100644
--- a/packages/pigeon/lib/generator_tools.dart
+++ b/packages/pigeon/lib/generator_tools.dart
@@ -13,7 +13,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '15.0.3';
+const String pigeonVersion = '16.0.0';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
diff --git a/packages/pigeon/lib/java_generator.dart b/packages/pigeon/lib/java_generator.dart
index 27c5a258187..43b42c40e90 100644
--- a/packages/pigeon/lib/java_generator.dart
+++ b/packages/pigeon/lib/java_generator.dart
@@ -448,10 +448,7 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
       });
 
       for (final Method func in api.methods) {
-        final String resultType =
-            func.returnType.isNullable || func.returnType.isVoid
-                ? 'NullableResult'
-                : 'Result';
+        final String resultType = _getResultType(func.returnType);
         final String returnType = func.returnType.isVoid
             ? 'Void'
             : _javaTypeForDartType(func.returnType);
@@ -459,8 +456,8 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
         addDocumentationComments(
             indent, func.documentationComments, _docCommentSpec);
         if (func.parameters.isEmpty) {
-          indent.write(
-              'public void ${func.name}(@NonNull $resultType<$returnType> result) ');
+          indent
+              .write('public void ${func.name}(@NonNull $resultType result) ');
           sendArgument = 'null';
         } else {
           final Iterable<String> argTypes = func.parameters
@@ -480,7 +477,7 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
               map2(argTypes, argNames, (String x, String y) => '$x $y')
                   .join(', ');
           indent.write(
-              'public void ${func.name}($argsSignature, @NonNull $resultType<$returnType> result) ');
+              'public void ${func.name}($argsSignature, @NonNull $resultType result) ');
         }
         indent.addScoped('{', '}', () {
           const String channel = 'channel';
@@ -515,7 +512,7 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
                 }
                 indent.addScoped('else {', '}', () {
                   if (func.returnType.isVoid) {
-                    indent.writeln('result.success(null);');
+                    indent.writeln('result.success();');
                   } else {
                     const String output = 'output';
                     final String outputExpression;
@@ -635,10 +632,7 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
   ///   int add(int x, int y);
   void _writeInterfaceMethod(JavaOptions generatorOptions, Root root,
       Indent indent, Api api, final Method method) {
-    final String resultType =
-        method.returnType.isNullable || method.returnType.isVoid
-            ? 'NullableResult'
-            : 'Result';
+    final String resultType = _getResultType(method.returnType);
     final String nullableType = method.isAsynchronous
         ? ''
         : _nullabilityAnnotationFromType(method.returnType);
@@ -657,10 +651,7 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
       }));
     }
     if (method.isAsynchronous) {
-      final String returnType = method.returnType.isVoid
-          ? 'Void'
-          : _javaTypeForDartType(method.returnType);
-      argSignature.add('@NonNull $resultType<$returnType> result');
+      argSignature.add('@NonNull $resultType result');
     }
     if (method.documentationComments.isNotEmpty) {
       addDocumentationComments(
@@ -752,16 +743,17 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
                     ? ' == null ? null : $resultValue.index'
                     : '.index';
               }
-              final String resultType =
-                  method.returnType.isNullable || method.returnType.isVoid
-                      ? 'NullableResult'
-                      : 'Result';
+              final String resultType = _getResultType(method.returnType);
+              final String resultParam =
+                  method.returnType.isVoid ? '' : '$returnType result';
+              final String addResultArg =
+                  method.returnType.isVoid ? 'null' : '$resultValue$enumTag';
               const String resultName = 'resultCallback';
               indent.format('''
-$resultType<$returnType> $resultName =
-\t\tnew $resultType<$returnType>() {
-\t\t\tpublic void success($returnType result) {
-\t\t\t\twrapped.add(0, $resultValue$enumTag);
+$resultType $resultName =
+\t\tnew $resultType() {
+\t\t\tpublic void success($resultParam) {
+\t\t\t\twrapped.add(0, $addResultArg);
 \t\t\t\treply.reply(wrapped);
 \t\t\t}
 
@@ -901,6 +893,19 @@ $resultType<$returnType> $resultName =
           .writeln('/** Failure case callback method for handling errors. */');
       indent.writeln('void error(@NonNull Throwable error);');
     });
+
+    indent.writeln(
+        '/** Asynchronous error handling return type for void API method returns. */');
+    indent.write('public interface VoidResult ');
+    indent.addScoped('{', '}', () {
+      indent
+          .writeln('/** Success case callback method for handling returns. */');
+      indent.writeln('void success();');
+      indent.newln();
+      indent
+          .writeln('/** Failure case callback method for handling errors. */');
+      indent.writeln('void error(@NonNull Throwable error);');
+    });
   }
 
   void _writeErrorClass(Indent indent) {
@@ -1108,3 +1113,14 @@ String _castObject(NamedType field, String varName) {
     return _cast(varName, javaType: hostDatatype.datatype);
   }
 }
+
+/// Returns string of Result class type for method based on [TypeDeclaration].
+String _getResultType(TypeDeclaration type) {
+  if (type.isVoid) {
+    return 'VoidResult';
+  }
+  if (type.isNullable) {
+    return 'NullableResult<${_javaTypeForDartType(type)}>';
+  }
+  return 'Result<${_javaTypeForDartType(type)}>';
+}
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java
index cc9ffe0ff14..a99aa2ef913 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java
@@ -14,6 +14,7 @@
 import com.example.alternate_language_test_plugin.CoreTests.HostIntegrationCoreApi;
 import com.example.alternate_language_test_plugin.CoreTests.NullableResult;
 import com.example.alternate_language_test_plugin.CoreTests.Result;
+import com.example.alternate_language_test_plugin.CoreTests.VoidResult;
 import io.flutter.embedding.engine.plugins.FlutterPlugin;
 import java.util.List;
 import java.util.Map;
@@ -208,8 +209,8 @@ public void throwErrorFromVoid() {
   }
 
   @Override
-  public void noopAsync(@NonNull NullableResult<Void> result) {
-    result.success(null);
+  public void noopAsync(@NonNull VoidResult result) {
+    result.success();
   }
 
   @Override
@@ -218,7 +219,7 @@ public void throwAsyncError(@NonNull NullableResult<Object> result) {
   }
 
   @Override
-  public void throwAsyncErrorFromVoid(@NonNull NullableResult<Void> result) {
+  public void throwAsyncErrorFromVoid(@NonNull VoidResult result) {
     result.error(new RuntimeException("An error"));
   }
 
@@ -338,7 +339,7 @@ public void echoAsyncNullableEnum(
   }
 
   @Override
-  public void callFlutterNoop(@NonNull NullableResult<Void> result) {
+  public void callFlutterNoop(@NonNull VoidResult result) {
     flutterApi.noop(result);
   }
 
@@ -348,7 +349,7 @@ public void callFlutterThrowError(@NonNull NullableResult<Object> result) {
   }
 
   @Override
-  public void callFlutterThrowErrorFromVoid(@NonNull NullableResult<Void> result) {
+  public void callFlutterThrowErrorFromVoid(@NonNull VoidResult result) {
     flutterApi.throwErrorFromVoid(result);
   }
 
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
index fae6d3d289b..8585b13315a 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java
@@ -980,6 +980,14 @@ public interface NullableResult<T> {
     /** Failure case callback method for handling errors. */
     void error(@NonNull Throwable error);
   }
+  /** Asynchronous error handling return type for void API method returns. */
+  public interface VoidResult {
+    /** Success case callback method for handling returns. */
+    void success();
+
+    /** Failure case callback method for handling errors. */
+    void error(@NonNull Throwable error);
+  }
 
   private static class HostIntegrationCoreApiCodec extends StandardMessageCodec {
     public static final HostIntegrationCoreApiCodec INSTANCE = new HostIntegrationCoreApiCodec();
@@ -1139,7 +1147,7 @@ AllNullableTypes sendMultipleNullableTypes(
      * A no-op function taking no arguments and returning no value, to sanity test basic
      * asynchronous calling.
      */
-    void noopAsync(@NonNull NullableResult<Void> result);
+    void noopAsync(@NonNull VoidResult result);
     /** Returns passed in int asynchronously. */
     void echoAsyncInt(@NonNull Long anInt, @NonNull Result<Long> result);
     /** Returns passed in double asynchronously. */
@@ -1162,7 +1170,7 @@ void echoAsyncMap(
     /** Responds with an error from an async function returning a value. */
     void throwAsyncError(@NonNull NullableResult<Object> result);
     /** Responds with an error from an async void function. */
-    void throwAsyncErrorFromVoid(@NonNull NullableResult<Void> result);
+    void throwAsyncErrorFromVoid(@NonNull VoidResult result);
     /** Responds with a Flutter error from an async function returning a value. */
     void throwAsyncFlutterError(@NonNull NullableResult<Object> result);
     /** Returns the passed object, to test async serialization and deserialization. */
@@ -1192,11 +1200,11 @@ void echoAsyncNullableMap(
     /** Returns the passed enum, to test asynchronous serialization and deserialization. */
     void echoAsyncNullableEnum(@Nullable AnEnum anEnum, @NonNull NullableResult<AnEnum> result);
 
-    void callFlutterNoop(@NonNull NullableResult<Void> result);
+    void callFlutterNoop(@NonNull VoidResult result);
 
     void callFlutterThrowError(@NonNull NullableResult<Object> result);
 
-    void callFlutterThrowErrorFromVoid(@NonNull NullableResult<Void> result);
+    void callFlutterThrowErrorFromVoid(@NonNull VoidResult result);
 
     void callFlutterEchoAllTypes(@NonNull AllTypes everything, @NonNull Result<AllTypes> result);
 
@@ -2097,9 +2105,9 @@ static void setUp(
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                NullableResult<Void> resultCallback =
-                    new NullableResult<Void>() {
-                      public void success(Void result) {
+                VoidResult resultCallback =
+                    new VoidResult() {
+                      public void success() {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
                       }
@@ -2434,9 +2442,9 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                NullableResult<Void> resultCallback =
-                    new NullableResult<Void>() {
-                      public void success(Void result) {
+                VoidResult resultCallback =
+                    new VoidResult() {
+                      public void success() {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
                       }
@@ -2834,9 +2842,9 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                NullableResult<Void> resultCallback =
-                    new NullableResult<Void>() {
-                      public void success(Void result) {
+                VoidResult resultCallback =
+                    new VoidResult() {
+                      public void success() {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
                       }
@@ -2892,9 +2900,9 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                NullableResult<Void> resultCallback =
-                    new NullableResult<Void>() {
-                      public void success(Void result) {
+                VoidResult resultCallback =
+                    new VoidResult() {
+                      public void success() {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
                       }
@@ -3574,7 +3582,7 @@ public FlutterIntegrationCoreApi(@NonNull BinaryMessenger argBinaryMessenger) {
     /**
      * A no-op function taking no arguments and returning no value, to sanity test basic calling.
      */
-    public void noop(@NonNull NullableResult<Void> result) {
+    public void noop(@NonNull VoidResult result) {
       final String channelName =
           "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noop";
       BasicMessageChannel<Object> channel =
@@ -3591,7 +3599,7 @@ public void noop(@NonNull NullableResult<Void> result) {
                         (String) listReply.get(1),
                         (String) listReply.get(2)));
               } else {
-                result.success(null);
+                result.success();
               }
             } else {
               result.error(createConnectionError(channelName));
@@ -3626,7 +3634,7 @@ public void throwError(@NonNull NullableResult<Object> result) {
           });
     }
     /** Responds with an error from an async void function. */
-    public void throwErrorFromVoid(@NonNull NullableResult<Void> result) {
+    public void throwErrorFromVoid(@NonNull VoidResult result) {
       final String channelName =
           "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.throwErrorFromVoid";
       BasicMessageChannel<Object> channel =
@@ -3643,7 +3651,7 @@ public void throwErrorFromVoid(@NonNull NullableResult<Void> result) {
                         (String) listReply.get(1),
                         (String) listReply.get(2)));
               } else {
-                result.success(null);
+                result.success();
               }
             } else {
               result.error(createConnectionError(channelName));
@@ -4251,7 +4259,7 @@ public void echoNullableEnum(
      * A no-op function taking no arguments and returning no value, to sanity test basic
      * asynchronous calling.
      */
-    public void noopAsync(@NonNull NullableResult<Void> result) {
+    public void noopAsync(@NonNull VoidResult result) {
       final String channelName =
           "dev.flutter.pigeon.pigeon_integration_tests.FlutterIntegrationCoreApi.noopAsync";
       BasicMessageChannel<Object> channel =
@@ -4268,7 +4276,7 @@ public void noopAsync(@NonNull NullableResult<Void> result) {
                         (String) listReply.get(1),
                         (String) listReply.get(2)));
               } else {
-                result.success(null);
+                result.success();
               }
             } else {
               result.error(createConnectionError(channelName));
@@ -4358,7 +4366,7 @@ public interface HostSmallApi {
 
     void echo(@NonNull String aString, @NonNull Result<String> result);
 
-    void voidVoid(@NonNull NullableResult<Void> result);
+    void voidVoid(@NonNull VoidResult result);
 
     /** The codec used by HostSmallApi. */
     static @NonNull MessageCodec<Object> getCodec() {
@@ -4407,9 +4415,9 @@ public void error(Throwable error) {
           channel.setMessageHandler(
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
-                NullableResult<Void> resultCallback =
-                    new NullableResult<Void>() {
-                      public void success(Void result) {
+                VoidResult resultCallback =
+                    new VoidResult() {
+                      public void success() {
                         wrapped.add(0, null);
                         reply.reply(wrapped);
                       }
diff --git a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java
index 819b2b37487..188c1d49aad 100644
--- a/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java
+++ b/packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/test/java/com/example/alternate_language_test_plugin/AsyncTest.java
@@ -24,8 +24,8 @@ public void echo(@NonNull String value, Result<String> result) {
     }
 
     @Override
-    public void voidVoid(NullableResult<Void> result) {
-      result.success(null);
+    public void voidVoid(VoidResult result) {
+      result.success();
     }
   }
 
@@ -36,7 +36,7 @@ public void echo(@NonNull String value, Result<String> result) {
     }
 
     @Override
-    public void voidVoid(NullableResult<Void> result) {
+    public void voidVoid(VoidResult result) {
       result.error(new Exception("error"));
     }
   }
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index 09b82181453..c820df9256f 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 15.0.3 # This must match the version in lib/generator_tools.dart
+version: 16.0.0 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: ">=3.0.0 <4.0.0"
diff --git a/packages/pigeon/test/java_generator_test.dart b/packages/pigeon/test/java_generator_test.dart
index 3754d3f2b04..cba2d702255 100644
--- a/packages/pigeon/test/java_generator_test.dart
+++ b/packages/pigeon/test/java_generator_test.dart
@@ -397,8 +397,8 @@ void main() {
     expect(
         code,
         contains(
-            'public void doSomething(@NonNull Input arg0Arg, @NonNull NullableResult<Void> result)'));
-    expect(code, contains('result.success(null);'));
+            'public void doSomething(@NonNull Input arg0Arg, @NonNull VoidResult result)'));
+    expect(code, contains('result.success();'));
   });
 
   test('gen host void argument api', () {
@@ -1307,7 +1307,7 @@ void main() {
     expect(
         code,
         contains(
-            'public void doit(@Nullable Long fooArg, @NonNull NullableResult<Void> result) {'));
+            'public void doit(@Nullable Long fooArg, @NonNull VoidResult result) {'));
   });
 
   test('background platform channel', () {

From ad3bd09a74f524145bed489b3dcbd821c3c8d3eb Mon Sep 17 00:00:00 2001
From: tarrinneal <tarrinneal@gmail.com>
Date: Wed, 3 Jan 2024 21:27:26 -0800
Subject: [PATCH 5/5] gen

---
 .../app/src/main/java/io/flutter/plugins/Messages.java    | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java b/packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java
index 5d1b693b823..1167e53d5fb 100644
--- a/packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java
+++ b/packages/pigeon/example/app/android/app/src/main/java/io/flutter/plugins/Messages.java
@@ -216,6 +216,14 @@ public interface NullableResult<T> {
     /** Failure case callback method for handling errors. */
     void error(@NonNull Throwable error);
   }
+  /** Asynchronous error handling return type for void API method returns. */
+  public interface VoidResult {
+    /** Success case callback method for handling returns. */
+    void success();
+
+    /** Failure case callback method for handling errors. */
+    void error(@NonNull Throwable error);
+  }
 
   private static class ExampleHostApiCodec extends StandardMessageCodec {
     public static final ExampleHostApiCodec INSTANCE = new ExampleHostApiCodec();