scrollDown method
Implementation
@override
void scrollDown(int pixels) {
ScrollerViewState? view = findListenerOfExactType(ScrollerViewState);
if (view == null) return;
if (view.controller.position.pixels >=
view.controller.position.maxScrollExtent) return;
var to = view.controller.offset + pixels;
to = (to > view.controller.position.maxScrollExtent)
? view.controller.position.maxScrollExtent
: to;
view.controller.jumpTo(to);
}