title: The getter 'uid' not defined
body: <p>i'm trying to create a food track app on android studio, it's my first time and i'm working with firebase_auth 3.3.12. my code in the aut.dart is:</p>
  <pre><code>import 'package:firebase_auth/firebase_auth.dart';
  import 'package:my_firstapp/models/user_model.dart';
  
  class AuthService {
  
    final FirebaseAuth _auth = FirebaseAuth.instance;
  
    AuthService();
  
    // create user object based on FirebaseUser.
    UserModel _userFromUser(User) {
      return user != null ? UserModel(uid: user.uid) : null;
    }
  
    // auth change user stream
    Stream&lt;UserModel&gt; get user {
      return _auth.authStateChanges()
          .map(_userFromUser);
  
    }
  
    Future&lt;UserModel&gt; getUser() async {
      User user = await _auth.currentUser();
      return _userFromUser(user);
    }
  
    // sign in with email and password
    Future signInWithEmailAndPassword(String email, String password) async {
      try {
        UserCredential result = await _auth.signInWithEmailAndPassword(email: email, password: password);
        User user = result.user;
        return _userFromUser(user);
      } catch(e) {
        print(e.toString());
        return null;
      }
    }
  
    // sign up with email and password
    Future registerWithEmailAndPassword(String email, String password) async {
      try {
        UserCredential result = await _auth.createUserWithEmailAndPassword(email: email, password: password);
        User user = result.user;
        // create a new user document in database
        return _userFromUser(user);
      } catch(e) {
        print(e.toString());
        return null;
      }
    }
  
    // sign out
    Future signOut() async {
      try {
        return await _auth.signOut();
      } catch(e){
        print(e.toString());
        return null;
      }
    }
  
  }
  </code></pre>
  <p>However i'm getting 2 errors:
  -The getter 'uid' isn't defined for the type 'Stream';
  -The expression &quot;await _auth.currentUser()&quot; doesn't evaluate to a function, so it can't be invoked.</p>
  <p>How can i rewrite the code? thanks</p>