/// <summary>
 /// Execute login command.
 /// </summary>
 /// <returns></returns>
 private async Task LoginExecuteCommand()
 {
     try
     {
         var user = await _authSvc.Authorize(MobileServiceAuthenticationProvider.Google);
     }
     catch (InvalidOperationException ex)
     {
         if (ex.Message.Contains("Authentication was canceled by the user"))
         {
         }
     }
     catch (Exception)
     {
         var page = new ContentPage();
         page.DisplayAlert("Error", "Error logging in. Please check connectivity and try again.", "OK");
     }
 }