title: Flutter add item to list
body: <p>I would like to add an item to a list:</p>
  
  <pre><code>void submitAll() async {
  List&lt;UserSearchItem&gt; userSearchItems = [];
  Firestore.instance
      .collection('insta_users')
      .snapshots()
      .listen((data) =&gt;
      data.documents.forEach((doc){
        print(data.documents.length);
  
        User user = new User.fromDocument(doc);
        UserSearchItem searchItem = new UserSearchItem(user);
        userSearchItems.add(searchItem);
        print(user.bio);
  
      }));
  print("Loaded");
  print(userSearchItems.length);
  }
  </code></pre>
  
  <p>But if I print the length of the list to the console, it always says, the list is 0 long...</p>
  
  <pre><code>print(userSearchItems.length);
  </code></pre>
  
  <p>Any suggegstions?</p>
  
  <p>Best Regards</p>