Remove confusing SWBDispatchQueue.async overload

This overload was only meant to be used in one place, and its behavior was a little confusing, since it does not actually run the work on the queue. Over time, this overload got used in a few other places due to overload resolution picking it up, and turning formerly synchronous work asynchronous. Remove it to restore the intended behavior.

Author: jakepetroules

Sources/SWBServiceCore/ServiceHostConnection.swift

@@ -46,9 +46,6 @@ final class ServiceHostConnection: @unchecked Sendable {
     /// Whether the queue is suspended.
     private let isSuspended = LockedValue(true)
 
-    /// The queue used to read incoming messages.
-    private let receiveQueue: SWBQueue
-
     /// The queue used to send outgoing messages.
     private let sendQueue: SWBQueue
 
@@ -69,7 +66,6 @@ final class ServiceHostConnection: @unchecked Sendable {
         self.inputFD = inputFD
         self.outputFD = outputFD
         // The queues for the service host connection are given .userInitiated QOS (not .utility, which most queues in Swift Build have) because we don't know whether we're servicing a user interaction request.  Most requests should be shunted to a background thread unless there's a reason to send a quick response at high priority.
-        self.receiveQueue = SWBQueue(label: "SWBBuildService.ServiceHostConnection.receiveQueue", qos: .userInitiated, autoreleaseFrequency: .workItem)
         self.sendQueue = SWBQueue(label: "SWBBuildService.ServiceHostConnection.sendQueue", qos: .userInitiated, autoreleaseFrequency: .workItem)
     }
 
@@ -136,7 +132,7 @@ final class ServiceHostConnection: @unchecked Sendable {
 
         // Otherwise, launch the receive pump.
         isSuspended.withLock { $0 = false }
-        receiveQueue.async {
+        Task<Void, Never>(priority: .userInitiated) {
             // Read data forever.
             var data: [UInt8] = []
             let tmpBufferSize = 4096

Sources/SWBUtil/SWBDispatch.swift

@@ -282,17 +282,8 @@ public final class SWBQueue: Sendable {
         }
     }
 
-    public func async(group: SWBDispatchGroup? = nil, execute body: @escaping @Sendable () -> Void) {
-        return queue.async(group: group?.group, execute: body)
-    }
-
-    // Temporary hack until rdar://98401196 (Use Swift Concurrency for low-level IO in ServiceHostConnection) lands. This should be safe because we only ever call `async` once in the place we use this.
-    public func async(qos: SWBQoS = .unspecified, execute work: @Sendable @escaping () async -> Void) {
-        queue.async(group: nil, qos: qos.dispatchQoS, flags: []) {
-            Task {
-                await work()
-            }
-        }
+    public func async(group: SWBDispatchGroup? = nil, qos: SWBQoS = .unspecified, execute body: @escaping @Sendable () -> Void) {
+        return queue.async(group: group?.group, qos: qos.dispatchQoS, execute: body)
     }
 
     public static func global() -> Self {