Cross-monitor borderless fullscreen window

[kognise]

I'm building a tool, primarily targetting macOS, that needs to render graphics fullscreen across all monitors.

What's the best way to do this with winit? Marking windows as fullscreen doesn't work, since that only goes on one monitor and multiple fullscreen windows can't be in view at once. Setting the coordinates to 0, 0 doesn't work either as that just positions it below the menubar at the top.

I also tried manually calling setLevel on the NSWindow with NSMainMenuWindowLevel+1 as the level, but that had absolutely no effect.