anchor.diff:  
       final List<vm_service.IsolateRef> refs = <vm_service.IsolateRef>[];
       for (final FlutterView flutterView in flutterViews) {
  -      if (flutterView.uiIsolate != null) {
  -        refs.add(flutterView.uiIsolate);
  +      final vm_service.IsolateRef uiIsolate = flutterView.uiIsolate;
  +      if (uiIsolate != null) {
  +        refs.add(uiIsolate);
         }
       }
       return refs;
  
positive.code:     isolateEvents = service.onIsolateEvent.listen((vm_service.Event event) {
        if (event.kind == vm_service.EventKind.kServiceExtensionAdded
            && event.extensionRPC == extensionName) {
          isolateEvents.cancel();
          extensionAdded.complete(event.isolate);
        }
      });
  
negative.code:   while (socket == null) {
      attempts += 1;
      try {
        socket = await constructor(url, compression: compression, logger: logger);
      } on io.WebSocketException catch (e) {
        await handleError(e);
      } on io.SocketException catch (e) {
  