popUntil function
循环pop 直到pop至指定页面
Implementation
void popUntil(RoutePredicate predicate) {
assert(FlExtended().navigatorKey.currentState != null,
'Set FlExtended().navigatorKey to one of [MaterialApp CupertinoApp WidgetsApp]');
return FlExtended().navigatorKey.currentState!.popUntil(predicate);
}