@override
void didUpdateWidget(convariant MyWidget oldWidget) {
  super.didUpdateWidget(oldWidget);
  
  if (oldWidget.path != widget.path) {
    _pagingController.removePageRequestListener(_pageRequestListener!);
    _pageRequestListener = null;

    _pageRequestListener = (pageKey) async {
      // This is where we use viewModel.
    }

    _pagingController.addPageRequestListener(_pageRequestListener!);
    _pagingController.refresh();
  }
}