Is there any way to gracefully cancel the RequestShapeAsync task? I do not have much experience with using the C# async capabilities, but it seems the awaitable method needs to accept a cancellation token and this method does not appear to accept one. Is there any other way to cancel this method gracefully? For example, if a user is in the middle of drawing a polygon does not want to finish it, I need a way to cancel this task by clicking a cancel button.