onPanUpdate method
Implementation
@override
void onPanUpdate(DragUpdateDetails details) {
final vd = scrollController.position.viewportDimension;
final jumpPos = switch (scrollController.position.axis) {
Axis.horizontal => details.delta.dx,
Axis.vertical => details.delta.dy,
};
final localPos = details.localPosition;
if (localPos.dy > vd || localPos.dy < 0) {
startAutoScroll(jumpPos);
} else {
stopAutoScroll();
}
}