private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            AsyncLoop();
        }

        async Task AsyncLoop()
        {
            while (true)
            {
                string result = await LoadNextItem();
                lbl1.Content = result;
            }
        }

        private static int ir11 = 0;
        async Task<string> LoadNextItem()
        {
            ir11++;
            return "aa " + ir11;
        }