Setting `desired_maximum_frame_latency` to a low value should
theoretically lead to lower latency in winit apps using `egui-wgpu`
(e.g. in `eframe` with `wgpu` backend).
* Replaces https://github.com/emilk/egui/pull/3714
* See also https://github.com/gfx-rs/wgpu/pull/4899
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It seems like `desired_maximum_frame_latency` has no effect on my Mac. I
lowered my monitor refresh-rate to 30Hz to test, and can see no
difference between `desired_maximum_frame_latency` of `0` or `3`.
Before when experimenting with changing the global `DESIRED_NUM_FRAMES`
in `wgpu` I saw a huge difference, so I wonder what has changed.
I verified that `set_maximum_drawable_count` is being called with either
`1` or `2`, but I perceive no difference between the two.
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