anchor.diff:  import 'package:analysis_server_client/handler/notification_handler.dart';
   import 'package:analysis_server_client/listener/server_listener.dart';
   import 'package:analysis_server_client/protocol.dart';
  -import 'package:analysis_server_client/server.dart';
  +import 'package:nnbd_migration/isolate_server.dart';
   import 'package:args/command_runner.dart';
   import 'package:cli_util/cli_logging.dart';
   import 'package:nnbd_migration/src/messages.dart';
  
positive.code:       await server.start(
            clientId: 'dart $name',
            clientVersion: _dartSdkVersion,
            enableAsserts: enableAsserts,
            instrumentationLogFile: instrumentationLogFile,
            profileServer: profileServer,
            serverPath: serverPath,
            servicesPort: servicesPort,
            sdkPath: sdkPath);
        _ServerNotifications serverNotifications = _ServerNotifications(server);
        await serverNotifications.listenToServer(server);
  
negative.code: 
      Map<String, List<AnalysisError>> fileErrors = {};
  
      String instrumentationLogFile;
      String sdkPath = options.sdkPath;
      bool stdioPassthrough = false;
  
      if (options.debug) {
        stdioPassthrough = true;
        instrumentationLogFile = path.join(
            Directory.systemTemp.createTempSync('migration_debug').path,
  