Wayland frame requests without rendering

[mahkoh]

Description

For event-driven applications it is sometimes desirable to always render in response to frame request callbacks. Currently there is no way to ensure the delivery of a frame callback without either presenting via the WSI or manually performing wayland requests.

It is already possible to create frame requests at any point. But winit provides no API to commit such a frame request.

Relevant platforms

Wayland

[kchibisov]

From what I remember it was recommended to not do so, and if you draw from idle you should draw immediately since frame callbacks don't help here?

I generally don't mind it once we have a a direct access to wayland backend.