This is only tangentially related, but libuv and mio's Windows implementations use the undocumented AFD readiness-based poll interface [1], since there isn't a documented readiness-based interface on Windows. The undocumented interface is now effectively stable since, among other reasons, Microsoft uses Tokio in some of its products.

[1] https://github.com/tokio-rs/mio/blob/master/src/sys/windows/...