dart: fix

lib/widgets/src/countdown_time_text.dart

@@ -35,7 +35,7 @@ class _CountdownTimeTextState extends State<CountdownTimeText> {
     super.dispose();
   }
 
-  _onUpdateTime(_) {
+  void _onUpdateTime(_) {
     final now = DateTime.now();
     final dur = widget.targetTime.difference(now);
     setState(() {

lib/widgets/widgets.dart

@@ -212,7 +212,7 @@ class LoadingWidget<T> extends HookConsumerWidget {
   }
 }
 
-addPostFrameCallback(Function() callback) {
+void addPostFrameCallback(Function() callback) {
   WidgetsBinding.instance.addPostFrameCallback((_) {
     callback();
   });