How to change renderers that change with time

Hi Xamarin Experts,

Normally, when one creates a custom renderer, BindableProperty is used, and in the custom Renderer, OnElementPropertyChanged is called which alters something in the view.

If I want to regularly update a view, it seems I cannot invalidate it from within the view itself - the event seems to need to come from the main event loop. This sort of makes sense to me, since all drawing should be done on the UI thread.

However, this begs the question- how does one use BindableProperty that can trigger an async function to update the UI from the main thread? I'm just not getting this.

Thanks a lot,
Mike