I'm working on an iPad app, which I want to be able to run properly on the M1 Mac. I am not using Mac Catalyst because I am using OpenGL, which is not available for Catalyst. Instead, I am targeting "My Mac(Designed for iPad) when I build for the M1 Mac. I would like to know when my app has been placed in full screen mode (when running on the M1 Mac). MacOS (AppKit?) provides the "NSWindowDidEnterFullScreenNotification" to help with this. In general, I'd love to be able to access these "NSWindow*" notifications from within my iOS app, but specifically, I get the error: "Use of undeclared identifier 'NSWindowDidEnterFullScreenNotification' when I use "[NSNotificationCenter defaultCenter] addObserver" to get notified when my app goes full screen. Any ideas as to how I can bridge this gap between iOS and MacOS and get notifications from MacOS, without resorting to Mac Catalyst? This capability would be extremely useful.