anchor.diff:  }
   
   /// Invokes [callback] inside the given [zone] passing it [arg1], [arg2], and [arg3].
  -void _invoke3<A1, A2, A3>(void callback(A1 a1, A2 a2, A3 a3), Zone zone, A1 arg1, A2 arg2, A3 arg3) {
  +void _invoke3<A1, A2, A3>(void callback(A1 a1, A2 a2, A3 a3)/*?*/, Zone/*!*/ zone, A1 arg1, A2 arg2, A3 arg3) {
     if (callback == null)
       return;
   
  
positive.code: }
  
  /// Invokes [callback] inside the given [zone] passing it [arg].
  void _invoke1<A>(void callback(A a), Zone zone, A arg) {
    if (callback == null)
      return;
  
  
negative.code: //  * AndroidTouchProcessor.java
  const int _kPointerDataFieldCount = 28;
  
  PointerDataPacket/*!*/ _unpackPointerDataPacket(ByteData/*!*/ packet) {
    const int kStride = Int64List.bytesPerElement;
    const int kBytesPerPointerData = _kPointerDataFieldCount * kStride;
    final int length = packet.lengthInBytes ~/ kBytesPerPointerData;
  