public static async Task FadeOutBrush(this Page page, float seconds)
{
// Create the storyboard
var sb = new Storyboard();
// Add fade out animation
sb.AddFadeOutBrush(seconds);
// Start animating
sb.Begin(page);
// Make page visible
page.Visibility = Visibility.Visible;
//Wait for it to finish
await Task.Delay((int)(seconds * 1000));
}