public static Task BeginAsync(this Storyboard storyboard)
{
storyboard.ThrowIfNull("storyboard");
var tcs = new TaskCompletionSource <bool>();
EventHandler onComplete = null;
onComplete = (s, e) =>
{
// sure ref set to null.
storyboard.Completed -= onComplete;
tcs.SetResult(true);
};
storyboard.Completed += onComplete;
storyboard.Begin();
return(tcs.Task);
}
