Flutter bloc registration trouble - flutter

Question

I have bloc, which listen to changes of currentUser state from firebase.
AuthBloc({#required AuthService authService})
: assert(authService != null),
_authService = authService,
super(AuthInitial()) {
_userSubscription = _authService.currentUser
.listen((user) => add(AuthenticationUserChanged(user)));
}
Then add event and the event call this function
Stream<AuthState> _mapAuthenticationUserChangedToState(
AuthenticationUserChanged event) async* {
if (event.user != null) {
// TO GET CUSTOM USER FROM FIRESTORE because of expiration, etc.
var user = await _authService.getUser(event.user.uid);
if (user.expiration == "") {
yield NotAuthorized(user);
} else {
var isAfter =
DateTime.now().toUtc().isAfter(DateTime.fromMillisecondsSinceEpoch(
user.expiration.millisecondsSinceEpoch,
isUtc: false,
).toUtc());
if (isAfter) {
yield NotAuthorized(user);
} else {
yield Authenticated(event.user);
}
}
} else {
yield Unautheticated();
}
But in my RegisterCubit I have signUpSubmitted method, which creates Firebase user and immediately after this is called my AuthBloc, which make sense.
But in my Bloc i need my custom Firestore user, which i have to create after FirebaseUser creation(because I need UID and email).
And this is the problem.
Future<void> signUpFormSubmitted() async {
if (!state.status.isValidated) return;
emit(state.copyWith(status: FormzStatus.submissionInProgress));
try {
await _authService
.registerUser(state.email.value, state.password.value)
.then((value) async {
// THIS IS CALLED AFTER BLOC
// I NEED TO CALL IT AFTER _registerUser() but in front of BLOC
var user =
ApplicationUser(uid: value.user.uid, email: value.user.email);
await _authService.addUserToDocument(user);
});
emit(state.copyWith(status: FormzStatus.submissionSuccess));
} on Exception {
print(Exception);
emit(state.copyWith(status: FormzStatus.submissionFailure));
}
}
My AuthService methods
Future<UserCredential> registerUser(email, password) =>
_auth.createUserWithEmailAndPassword(email: email, password: password);
Future<void> addUserToDocument(ApplicationUser user) {
return _db.collection('users').doc(user.uid).set({
'uid': user.uid,
'firstname': '',
'lastname': '',
'age': '',
'expiration': '',
'email': user.email
});
}