[analysis_server] Remove unused dart:async imports

Change-Id: I764ee78cb9e31bdb3abaa36ca4754e1fed180311
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/161447
Auto-Submit: Mike Fairhurst <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>

Author: MichaelRFairhurst

pkg/analysis_server/benchmark/benchmarks.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math' as math;

pkg/analysis_server/benchmark/perf/flutter_analyze_benchmark.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 

pkg/analysis_server/lib/plugin/edit/fix/fix_core.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
     show SourceChange;

pkg/analysis_server/lib/src/analysis_server_abstract.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:core';
 import 'dart:io' as io;
 

pkg/analysis_server/lib/src/channel/channel.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:convert';
 
 import 'package:analysis_server/protocol/protocol.dart';

pkg/analysis_server/lib/src/cider/completion.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';

pkg/analysis_server/lib/src/cider/fixes.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/services/correction/change_workspace.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';

pkg/analysis_server/lib/src/computer/import_elements_computer.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/ast/ast.dart';

pkg/analysis_server/lib/src/domain_analysis.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol_constants.dart';

pkg/analysis_server/lib/src/domain_diagnostic.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol.dart';