wlr-layer-shell: detect occluded/suspended surface?

I'm hoping this is the right place for this question/feature request. I came across !201 (merged) which offers a mechanism in xdg-shell to detect if surface repaints have been suspended (due to occlusion or whatever). There's some discussion in that issue as to whether xdg-shell is the best place for that.

I currently have a use case where I need this behaviour. I'm using wlr-layer-shell to render a desktop widget (e.g. something like conky) beneath other windows, I want to suspend the fairly expensive polling and processing that goes on in the background if the widget is not visible. Especially on mobile devices this should make a positive impact on battery life. But as I currently understand it (which may well be flawed as my wayland experience is limited), I can't do this yet (as I'm not using xdg-shell and don't have a toplevel)?