Firebase Cloud Messaging for Flutter

FirebaseMessaging-Flutter.dart

final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
_firebaseMessaging.configure(
    onLaunch: (Map<String, dynamic> message) {
      print('onLaunch called');
    },
    onResume: (Map<String, dynamic> message) {
      print('onResume called');
    },
    onMessage: (Map<String, dynamic> message) {
      print('onMessage called');
    },
  );
  _firebaseMessaging.subscribeToTopic('all');
  _firebaseMessaging.requestNotificationPermissions(IosNotificationSettings(
    sound: true,
    badge: true,
    alert: true,
  ));
  _firebaseMessaging.onIosSettingsRegistered
      .listen((IosNotificationSettings settings) {
    print('Hello');
  });
  _firebaseMessaging.getToken().then((token) {
    print(token); // Print the Token in Console
  });
}

pubspec.yaml

dependencies:
  firebase_messaging: ^6.0.16

flutter packages get