controller property
Implementation
set controller(StickyCollapsablePanelController value) {
if (_controller == value) return;
value.precedingScrollExtent = _controller.precedingScrollExtent;
_controller = value;
}
set controller(StickyCollapsablePanelController value) {
if (_controller == value) return;
value.precedingScrollExtent = _controller.precedingScrollExtent;
_controller = value;
}