FirebaseMessaging messaging = FirebaseMessaging.instance;
NotificationSettings settings = await messaging.requestPermission(
alert: true,
announcement: false,
badge: true,
carPlay: false,
criticalAlert: false,
provisional: false,
sound: true,
);
if (settings.authorizationStatus == AuthorizationStatus.authorized) {
print('User granted permission');
} else if (settings.authorizationStatus == AuthorizationStatus.provisional) {
print('User granted provisional permission');
} else {
print('User declined or has not accepted permission');
}