anchor.diff:  import 'pointer_router.dart';
   import 'recognizer.dart';
   
  -typedef void GestureTapDownCallback(ui.Point globalPosition);
  -typedef void GestureTapUpCallback(ui.Point globalPosition);
  +typedef void GestureTapDownCallback(Point globalPosition);
  +typedef void GestureTapUpCallback(Point globalPosition);
   typedef void GestureTapCallback();
   typedef void GestureTapCancelCallback();
   
  
positive.code:     _gestureMap[pointer]?.reject();
    }
  
    void _resolveTap(int pointer, _TapResolution resolution, ui.Point globalPosition) {
      _gestureMap.remove(pointer);
      if (resolution == _TapResolution.tap) {
        if (onTapUp != null)
  
negative.code: // found in the LICENSE file.
  
  import 'dart:async';
  import 'dart:ui' show Point, Offset;
  
  import 'arena.dart';
  import 'constants.dart';
  