didOverscrollBy method

void didOverscrollBy (double value)

Called by setPixels to report overscroll when an attempt is made to change the pixels position. Overscroll is the amount of change that was not applied to the pixels value.

Implementation 

void didOverscrollBy(double value) {
  assert(activity.isScrolling);
  activity.dispatchOverscrollNotification(copyWith(), context.notificationContext, value);
}