Callback signature for LongPressGestureRecognizer.onLongPressStart.
Called when a pointer has remained in contact with the screen at the same location for a long period of time. Also reports the long press down position.
- GestureDetector.onLongPressStart, which matches this signature.
- GestureLongPressCallback, which is the same signature without the details.
typedef GestureLongPressStartCallback = void Function(LongPressStartDetails details);