title: flutter app is crashing on iOS with AppBar
body: <p>my app is working fine on android but for ios its crashing ,
  if i comment the AppBar , its working in ios, but with app its not working.</p>
  <p>appBar: AppBar(), // here is the problem</p>
  <pre><code> @override
    Widget build(BuildContext context) {
      final screenSize = MediaQuery.of(context).size;
      return Scaffold(
        key: _scaffoldKey,
        appBar: AppBar(), // here is the problem
        backgroundColor: Colors.black,
        body: SafeArea(
  </code></pre>
  <p>main.dart code,</p>
  <pre><code> @override
    Widget build(BuildContext context) {
      pushNotificationMessage();
      SystemChrome.setPreferredOrientations([
        DeviceOrientation.portraitUp,
        DeviceOrientation.portraitDown,
      ]);
      return MultiProvider(
        providers: [
          ChangeNotifierProvider&lt;AppData&gt;(create: (_) =&gt; AppData()),
        ],
        child: GetMaterialApp(
          title: 'ABC App',
          debugShowCheckedModeBanner: false,
  </code></pre>