public void SignInWithCustomToken(string token, FirebaseLoginPromise completedPromise)
 {
     Firebase.Auth.Auth.DefaultInstance.SignInWithCustomToken(token, (authResult, error) =>
     {
         completedPromise.OnComplete(error == null);
     });
 }
 public void SignInWithCustomToken(string token, FirebaseLoginPromise completedListener)
 {
     instance.SignInWithCustomToken(token).AddOnCompleteListener(new LoginCompletedListener(completedListener));
 }