title: Unity Firebase Invites throws exception ApplicationException: internal::IsInitialized()
body: <p>I'm trying to add Firebase Invites to my Unity game. I've followed all the tutorial steps and have set up seems like everything. But when I try to run the code from tutorial to send an invite, I'm getting an exception:</p>
  
  <pre><code>ApplicationException: internal::IsInitialized()
   at Firebase.FutureBase.status ()
   at Firebase.Invites.SendInviteFuture.GetTask (Firebase.Invites.SendInviteFuture fu)
   at Firebase.Invites.FirebaseInvites.SendInviteAsync (Firebase.Invites.Invite invite)
  ...
  </code></pre>
  
  <p>The code is:</p>
  
  <pre><code>void Start()
  {
      Firebase.FirebaseApp.CheckAndFixDependenciesAsync().ContinueWith(task =&gt;
      {
          dependencyStatus = task.Result;
          if (dependencyStatus == Firebase.DependencyStatus.Available)
              InitializeFirebase();
          else
              Debug.LogError("Could not resolve all Firebase dependencies: " + dependencyStatus);
      });
  }
  
  void InitializeFirebase()
  {
      Firebase.Invites.FirebaseInvites.InviteReceived += OnInviteReceived;
      Firebase.Invites.FirebaseInvites.InviteNotReceived += OnInviteNotReceived;
      Firebase.Invites.FirebaseInvites.ErrorReceived += OnErrorReceived;
  }
  
  public void ShowInviteBox(System.Action&lt;bool&gt; callback)
  {
    var invite = new Firebase.Invites.Invite() {
      TitleText = "Invites Test App",
      MessageText = "Please try my app! It's awesome.",
      CallToActionText = "Download it for FREE",
      DeepLinkUrl = new System.Uri("http://google.com/abc")
    };
    Firebase.Invites.FirebaseInvites.SendInviteAsync(invite).ContinueWith(HandleSentInvite);
  }
  </code></pre>
  
  <p>I use:</p>
  
  <ul>
  <li>Unity 2017.3.0f3 </li>
  <li>Google Play Game Services Plugin for Unity 0.9.50</li>
  <li>Firebase Invites 4.4.3 </li>
  <li>Appodeal 2.8.18 nodex </li>
  <li>Game Analytics 3.10.4</li>
  </ul>
  
  <p>Any help would be highly appreciated!</p>