private async void Median5x5PageMenuFlyoutItem_Click(object sender, RoutedEventArgs e)
        {
            MedianFilterHelper.MedianFilter(WriteableOutputImage, 5);

            AddToUndo(WriteableOutputImage.Clone());
            await UpdateOutputImage();
        }
        private async void MedianCustomPageMenuFlyoutItem_Click(object sender, RoutedEventArgs e)
        {
            MedianFilterDialog  dialog = new MedianFilterDialog();
            ContentDialogResult result = await dialog.ShowAsync();


            if (result == ContentDialogResult.Secondary)
            {
                MedianFilterHelper.MedianFilter(WriteableOutputImage, dialog.MaskSize);

                AddToUndo(WriteableOutputImage.Clone());
                await UpdateOutputImage();
            }
            else
            {
                // The user clicked the CLoseButton, pressed ESC, Gamepad B, or the system back button.
                // Do nothing.
            }
        }