found something interesting earlier, AVFoundation apparently has a performance hud: preferences are equivalent to `defaults write com.apple.avfoundation.videoperformancehud enable -int 1` and `defaults write com.apple.avfoundation.videoperformancehud fontsize -int 50`
(tested on iOS, but this probably works on macOS too)
(tested on iOS, but this probably works on macOS too)




