in nav2-usability/scenario_code/lib/skipping-stacks/router.dart [294:306]
Future<void> setNewRoutePath(AppRoutePath path) async {
if (path is AuthorRoutePath) {
_appState.selectedAuthorId = path.id;
} else if (path is AuthorsRoutePath) {
_appState.isViewingAuthorsPage = true;
} else if (path is BookRoutePath) {
_appState.selectedBookId = path.id;
} else {
_appState.clearSelectedBook();
_appState.clearSelectedAuthor();
_appState.isViewingAuthorsPage = false;
}
}