/// <summary>
 /// Method called when a page is popped off the Navigation stack,
 /// or when we pop to root.
 /// </summary>
 /// <param name="sender">NavigationPage</param>
 /// <param name="e">Details</param>
 void OnPagePopped(object sender, Xamarin.Forms.NavigationEventArgs e)
 {
     NavigatedBack?.Invoke(this, EventArgs.Empty);
 }
        public Task GoBackAsync()
        {
            NavigatedBack?.Invoke(this, EventArgs.Empty);

            return(Task.FromResult(0));
        }