WaitCancelled on macOS without other events

I was playing with nannou today and I noticed that their LoopMode::Wait is not working on macOS. This is intended to prevent rerenders unless an input or window event is received. It achieves this by using winit's ControlFlow::Wait under the hood. This works fine on Windows, but on macOS, the wait is interrupted (at 60fps), even though there are (as far as I can tell) no events requiring that the wait be interrupted.

I ran winit/examples/window.rs on my Macbook Pro and saw many instances of the following event sequence:

...
NewEvents(WaitCancelled { start: Instant { t: 1014694701148459 }, requested_resume: None })
MainEventsCleared
RedrawRequested(WindowId(Id(140590972026416)))
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 1014694701163499 }, requested_resume: None })
MainEventsCleared
RedrawRequested(WindowId(Id(140590972026416)))
RedrawEventsCleared
...

I have a couple questions regarding this behavior:

1. Is it expected that one would receive NewEvents when there don't seem to be any such events?
2. Does the winit API guarantee that your wait won't be interrupted if there are no new events?

If the answer to (2) is "no", it seems like the nannou LoopMode::Wait implementation will need to change, regardless of whether this is unexpected / buggy behavior.

Related issue in nannou: https://github.com/nannou-org/nannou/issues/781

Thanks! Let me know if I can help with anything.

Run winit/examples/window.rs on macOS and inspect the reported NewEvents(WaitCancelled) sequence around MainEventsCleared and RedrawRequested. Compare the observed behavior with ControlFlow::Wait and the related nannou issue; document whether the interruption is expected and whether the API guarantees an uninterrupted wait.