I am really hyped about this, man. I naturally went the same direction, selectors + threadpool, for the custom http server I made for my BBS (a weird juxtaposition of terms!). I knew that threads wouldn't be a limitation for me, and I wanted to write simple blocking code. The websockets support makes this an even bigger deal for some future stuff I want to do.
Have you added any countermeasures for various kinds of DoS attacks, such as the [headerLimit in asynchttpserver](https://github.com/nim-lang/Nim/blob/80e739f2bf5a3e40df7000566a9cbb9cfab29ac4/lib/pure/asynchttpserver.nim#L265-L269)? Then again, if you're running your nim server behind nginx (which is likely), I would guess that it would protect you from this kind of stuff.
