dispose method
override
Releases any resources used by the object.
This method is called by the owner of this gesture recognizer when the object is no longer needed (e.g. when a gesture recognizer is being unregistered from a GestureDetector, the GestureDetector widget calls this method).
Implementation
@override
void dispose() {
_stopDeadlineTimer();
_resetDragUpdateThrottle();
super.dispose();
}