anchor.diff:  import 'focus_manager.dart';
   import 'framework.dart';
   import 'gesture_detector.dart';
  -import 'media_query.dart';
   import 'notification_listener.dart';
   import 'primary_scroll_controller.dart';
   import 'restoration.dart';
  
positive.code:                   ..minFlingVelocity = _physics?.minFlingVelocity
                    ..maxFlingVelocity = _physics?.maxFlingVelocity
                    ..velocityTrackerBuilder = _configuration.velocityTrackerBuilder(context)
                    ..dragStartBehavior = widget.dragStartBehavior
                    ..gestureSettings = _mediaQueryData?.gestureSettings;
                },
              ),
            };
  
negative.code:                   ..minFlingVelocity = _physics?.minFlingVelocity
                    ..maxFlingVelocity = _physics?.maxFlingVelocity
                    ..velocityTrackerBuilder = _configuration.velocityTrackerBuilder(context)
                    ..dragStartBehavior = widget.dragStartBehavior;
                },
              ),
            };
  