private async void OnScreenshotButtonClicked(object sender, EventArgs e)
{
// Export the image from mapview and assign it to the imageview
_overlayImageView.Image = await Esri.ArcGISRuntime.UI.RuntimeImageExtensions.ToImageSourceAsync(await _myMapView.ExportImageAsync());
// Enable the button to close image view
_closeImageViewButton.Enabled = true;
// Show the overlay view
_overlayView.Hidden = false;
}