title: I/flutter (14318): NoSuchMethodError: Class 'FirebaseUser' has no instance getter 'firstname'
body: <p>I am trying to update the user profile of users of app I am building. The users information is stored in firebase, the app is coded in dart running on android. </p>
  
  <p>I have tried implementing example from <a href="https://firebase.google.com/docs/auth/web/manage-users" rel="nofollow noreferrer">https://firebase.google.com/docs/auth/web/manage-users</a> website.</p>
  
  <pre><code> 51   createUser() {
   52     if (checkFields()) {
   53       //Perform Login
   54       var user = FirebaseAuth.instance.currentUser();
   55       FirebaseAuth.instance
   56           .createUserWithEmailAndPassword(email: _email, password: _password)
   57           .then((user) {
   58             var  userUpdateInfo = new UserUpdateInfo();
   59             user.updateProfile(userUpdateInfo)
                      .then((user) {
   60                   userUpdateInfo.displayName = _Firstname;
   61                   FirebaseAuth.instance
                                    .currentUser()
                                    .then((user)  {
                                      UserManagement().storeNewuser(user, context);
   62                               })
                                    .catchError((e) {print(e);});
   63                 })
                      .catchError((e) {
   64                   print(e);
   65                 });
   66                 //UserManagement().storeNewuser(user, context);
   67                 Navigator.of(context).pop();
   68                 Navigator.of(context)
                               .pushReplacementNamed('/landingpage');
   69           })
                .catchError((e) {
   70             print("ivlvvliyviv");
   71           });
   72     }
   73   }
  </code></pre>
  
  <p>The app runs smoothly without does not crushing but when the user updates the firstname but it is not changed on firebase, line 60 was suppose to update the firstname field on firebase, and this is where I am adding my firstname field </p>
  
  <pre><code>Firestore.instance
           .collection('/users')
           .add({ 
             'email': user.email, 
             'uid': user.uid, 
             'firstname': user.firstname,
  </code></pre>