anchor.diff:  }
   
   class RTCVideoView extends StatefulWidget {
  -  final RTCVideoRenderer renderer;
  +  RTCVideoRenderer renderer;
     RTCVideoView(this.renderer);
     @override
     _RTCVideoViewState createState() => new _RTCVideoViewState(renderer);
   }
   
   class _RTCVideoViewState extends State<RTCVideoView> {
  -  final RTCVideoRenderer renderer;
  -  var aspectRatio = 1.0;
  +  RTCVideoRenderer renderer;
  +  double _aspectRatio;
   
     _RTCVideoViewState(this.renderer);
   
  
positive.code:   RTCVideoViewObjectFitCover,
  }
  
  typedef void VideoRotationChangeCallback(int textureId, int rotation);
  typedef void VideoSizeChangeCallback(
      int textureId, double width, double height);
  
  class RTCVideoRenderer {
    MethodChannel _channel = WebRTC.methodChannel();
  
negative.code:   int _rotation = 0;
    double _width = 0.0, _height = 0.0;
    bool _mirror;
    double _aspectRatio = 1.0;
    MediaStream _srcObject;
    RTCVideoViewObjectFit _objectFit =
        RTCVideoViewObjectFit.RTCVideoViewObjectFitContain;
    StreamSubscription<dynamic> _eventSubscription;
  
    VideoAspectRatioCallback onAspectRatioChanged;
  
    initialize() async {
      final Map<dynamic, dynamic> response =
  