anchor.diff:      var response =
           responseController.stream.firstWhere((response) => response.id == id);
       if (throwOnError) {
  -      errorCompleter = Completer<Response>();
  +      var completer = errorCompleter = Completer<Response>();
         try {
  -        return Future.any([response, errorCompleter.future]);
  +        return Future.any([response, completer.future]);
         } finally {
           errorCompleter = null;
         }
  
positive.code: // 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.
  
  // @dart = 2.9
  
  import 'dart:async';
  
  import 'package:analysis_server/protocol/protocol.dart';
  import 'package:analysis_server/src/analysis_server.dart';
  import 'package:analysis_server/src/channel/channel.dart';
  import 'package:analysis_server/src/plugin/notification_manager.dart';
  import 'package:analysis_server/src/plugin/plugin_manager.dart';
  
negative.code: /// A plugin manager that simulates broadcasting requests to plugins by
  /// hard-coding the responses.
  class TestPluginManager implements PluginManager {
    plugin.AnalysisSetPriorityFilesParams? analysisSetPriorityFilesParams;
    plugin.AnalysisSetSubscriptionsParams? analysisSetSubscriptionsParams;
    plugin.AnalysisUpdateContentParams? analysisUpdateContentParams;
    plugin.RequestParams? broadcastedRequest;
    Map<PluginInfo, Future<plugin.Response>>? broadcastResults;
  
    @override
    List<PluginInfo> plugins = [];
  