private async void MicrophoneIcon_Tapped(object sender, TappedRoutedEventArgs e)
        {
            if (_speechService == null)
            {
                _speechService = new SpeechService();
            }

            var notifier = NotifyTaskCompletion.Create(_speechService.RecognizeAsync());
            await notifier.TaskCompleted;

            if (notifier.IsSuccessfullyCompleted)
            {
                searchBox.Text = notifier.Result;
            }
        }