title: Flutter: How to listen to the FirebaseUser is Email verified boolean?
body: <p><strong>My Idea:</strong>
  I want to use the Firebase Auth Plugin in Flutter to register the users.
  But before they can access the App, they have to verify their Email address.
  Therefor I push the Firebase users after registration to a verification screen. This is just a loading screen which tells the user that he has to verify his email.</p>
  <p><strong>But now:</strong> How can I continuously listen, if the users email is verified or not and send him (when true) to the Homescreen?</p>
  <p>I'm new to Flutter and I don't know if I have to use a Streams or Observables or a while Loop or setState() or something else for such a boolean check. And I also don't know how to setup a solution.</p>
  <p>This is my basic code for register a user:</p>
  <pre><code>import 'package:cloud_firestore/cloud_firestore.dart';
  import 'dart:async';
  
  class AuthService {
    final FirebaseAuth _auth = FirebaseAuth.instance;
    final Firestore _db = Firestore.instance;
  
    Future&lt;FirebaseUser&gt; get getUser =&gt; _auth.currentUser();
  
    Stream&lt;FirebaseUser&gt; get user =&gt; _auth.onAuthStateChanged;
  
    Future&lt;FirebaseUser&gt; edubslogin(String email, String password) async {
      try {
        final FirebaseUser user = await _auth.createUserWithEmailAndPassword(
          email: email,
          password: password,
        );
       
        await user.sendEmailVerification();
        
        //email verification somewhere here
      
        updateUserData(user);
        return user;
      } catch (error) {
        print(error);
        return null;
      }
    }
  </code></pre>
  <p>I've tried this:</p>
  <pre><code>     if (user.isEmailVerified == true) {
          
          //go to Homescreen
          return true; 
        } else {
  
          //show verification screen(loading spinner)
          return false;
        }
  </code></pre>
  <p>But I don't get a boolean value <code>true</code> out of <code>isEmailVerified</code>.</p>
  <p>What do I have to do?</p>