lockForTopPage method
void
lockForTopPage()
Implementation
void lockForTopPage() {
var topPage = SplitRouterDelegate.instance.routePath.pageInstances
.lastWhere((page) =>
page.position == SplitRouterPosition.Right ||
page.position == SplitRouterPosition.Left);
lockPageStack.add(topPage);
updateKey.update();
_initListener();
}