Winit 0.31 draft

[lucasmerlin]

I was curious how much work the winit update would be, so I tried getting hello world simple to run.
It doesn't run yet but I got it to compile. Looks like this will be a lot of effort to get perfect. (Maybe time to remove the glow backend since the two backends add a lot of complexity?).

I commented a ton of code to try to get something to compile, so this will need a lot more work. Opening this mostly in case someone wants to pick up the work or discuss how we should do things.

[github-actions]

Preview is being built...

Preview will be available at https://egui-pr-preview.github.io/pr/7731-lucas/winit-0.31

View snapshot changes at kitdiff

[nicoburns]

Blitz main has now upgraded to Winit 0.31. The PR that we merged is here: DioxusLabs/blitz#323, but that includes adding support for Android and iOS as well. PR with only Winit-related changes is (but not quite all of the changes we finally applied) is here DioxusLabs/blitz#298

Some notes:

• We replaced the "UserEvent" functionality with a channel (std::mpsc). The architecture doesn't change much here. It just uses a custom channel that's read on the "proxy wake up" event rather than having Winit manage the channel.
• I've published https://docs.rs/accesskit_xplat which is a fork of accesskit_winit without depending on Winit (so it can be used with any Winit version).
• Other than that it was mostly just renaming things and adding dyn in a bunch of places.