XboxLiveUser.WindowsSystemUser is null... need it for GameSaveProvider

I need the WindowsSystemUser to create the GameSaveProvider. Am I doing this wrong? Is there some other way to get the WindowsSystemUser?

Here's my initialization for Connected Storage (UWP version is GameSaveProvider)

Code (CSharp):

1.         XboxLiveUser xboxLiveUser = UWPUser.Get().GetUser();
2.         if (null != xboxLiveUser)
3.         {
4.             var initTask = GameSaveProvider.GetForUserAsync(xboxLiveUser.WindowsSystemUser, s_scid).AsTask();
5.             if (initTask.Result.Status == GameSaveErrorStatus.Ok)
6.             {
7.                 this.gameSaveProvider = initTask.Result.Value;
8.             }
9.  
10.             this.m_isInitialized = true;
11.             if (null != onInit)
12.                 onInit(GameSaveErrorStatus.Ok == initTask.Result.Status);
13.         }
14.  

I got my XboxLiveUser from this:

Code (CSharp):

1.     private async void SignIn()
2.     {
3.         Debug.LogError("SignIn");
4.         SignInResult silentSignInResult = await m_user.SignInSilentlyAsync(m_dispatcher);
5.         bool signedIn = false;
6.         switch (silentSignInResult.Status)
7.         {
8.             case SignInStatus.Success:
9.         Debug.LogError("Success");
10.                 signedIn = true;
11.                 break;
12.             case SignInStatus.UserInteractionRequired:
13.         Debug.LogError("UserInteractionRequired");
14.                 SignInResult loudSignInResult = await m_user.SignInAsync(m_dispatcher);
15.                 switch (loudSignInResult.Status)
16.                 {
17.                     case SignInStatus.Success:
18.         Debug.LogError("Success");
19.                         signedIn = true;
20.         //m_service.UpdateAchievementAsync(m_user.XboxUserId, "3", 100);
21.                         break;
22.                     case SignInStatus.UserCancel:
23.         Debug.LogError("UserCancel");
24.                         // TODO: retry sign in
25.                         break;
26.                     default:
27.         Debug.LogError("default");
28.                         break;
29.                 }
30.                 break;
31.             case SignInStatus.UserCancel:
32.         Debug.LogError("UserCancel");
33.                 // TODO: retry or exit
34.                 break;
35.             default:
36.         Debug.LogError("default");
37.                 break;
38.         }
39.  
40.         if( signedIn )
41.         {
42.             m_context = new XboxLiveContext(m_user);
43.             Debug.LogError("User signed in: " + m_user.Gamertag);
44.         }
45.         else
46.         {
47.             Debug.LogError("No User");
48.         }
49.     }
50.  

 

If anyone is following along, I found this:
https://github.com/Microsoft/xbox-live-samples

The interesting bit is in this comment here:
// Getting a GameSaveProvider requires the Windows user object. It will automatically get the correct
// provider for the current Xbox Live user.

Code (CSharp):

1.     public async Task<GameSaveErrorStatus> Initialize(XboxLiveContext context)
2.     {
3.         if (context == null)
4.         {
5.             throw new ArgumentNullException("context");
6.         }
7.  
8.         // Getting a GameSaveProvider requires the Windows user object. It will automatically get the correct
9.         // provider for the current Xbox Live user.
10.         var users = await Windows.System.User.FindAllAsync();
11.  
12.         if (users.Count > 0)
13.         {
14.             GameSaveProviderGetResult result = await GameSaveProvider.GetForUserAsync(
15.                 users[0], context.AppConfig.ServiceConfigurationId);
16.             if (result.Status == GameSaveErrorStatus.Ok)
17.             {
18.                 m_context = context;
19.                 m_saveProvider = result.Value;
20.             }
21.  
22.             return result.Status;
23.         }
24.         else
25.         {
26.             throw new Exception("No Windows users found when creating save provider.");
27.         }
28.     }
29.