anchor.diff:    }, null);
   }
   
  -void _reportUnhandledException(String error, String stackTrace) native 'Window_reportUnhandledException';
  +void _reportUnhandledException(String/*!*/ error, String/*!*/ stackTrace) native 'Window_reportUnhandledException';
   
   /// Invokes [callback] inside the given [zone].
  -void _invoke(void callback(), Zone zone) {
  +void _invoke(void callback()/*?*/, Zone/*!*/ zone) {
     if (callback == null)
       return;
   
  
positive.code: 
  @pragma('vm:entry-point')
  // ignore: unused_element
  void _dispatchPlatformMessage(String name, ByteData data, int responseId) {
    if (name == ChannelBuffers.kControlChannelName) {
      try {
        channelBuffers.handleMessage(data);
  
negative.code: 
  @pragma('vm:entry-point')
  // ignore: unused_element
  void _dispatchPointerDataPacket(ByteData/*!*/ packet) {
    if (window.onPointerDataPacket != null)
      _invoke1<PointerDataPacket>(window.onPointerDataPacket, window._onPointerDataPacketZone, _unpackPointerDataPacket(packet));
  }
  
  @pragma('vm:entry-point')
  // ignore: unused_element
  void _dispatchSemanticsAction(int/*!*/ id, int/*!*/ action, ByteData/*?*/ args) {
    _invoke3<int, SemanticsAction, ByteData>(
      window.onSemanticsAction,
      window._onSemanticsActionZone,
  