HTTP/2.0 and HTTP/3.0

Support for HTTP/2.0 and the upcoming HTTP/3.0 would be epic. I know this requires some bigger changes (I think) since 3.0 needs multiple UDP connections but it should be possible.

I would try looking into how to do it using luv but it's quite a complex system built already.
Would this be something that could be implemented sufficiently well while still keeping the api stable.