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