anchor.diff:    bool get hasIsolate => _uiIsolate != null;
   
     Future<Null> flushUIThreadTasks() async {
  -    await owner.vm.invokeRpcRaw('_flutter.flushUIThreadTasks');
  +    await owner.vm.invokeRpcRaw('_flutter.flushUIThreadTasks',
  +      params: <String, dynamic>{'isolateId': _uiIsolate.id});
     }
   
     @override
  
positive.code:     assert(assetsDirectory != null);
      await owner.vmService.vm.invokeRpc('_flutter.setAssetBundlePath',
          params: <String, dynamic>{
            'viewId': id,
            'assetDirectory': assetsDirectory.toFilePath(windows: false)
          });
  
negative.code:     if (!isFlutterEngine)
        return;
      _viewCache.clear();
      for (Isolate isolate in isolates) {
        await vmService.vm.invokeRpc('_flutter.listViews',
            timeout: kLongRequestTimeout,
            params: <String, dynamic> {'isolateId': isolate.id});
      }
    }
  
    Iterable<FlutterView> get views => _viewCache.values;
  