Integrating uWebSockets with HTTP2

[Bolderaysky]

Hi,
I'm using uWebSockets in my project for some time as HTTP/WebSocket server and I want to integrate that with nghttp2. I want this, because that would allow to use HTTP2 as main protocol for talking with browser clients instead of HTTP1.1 and WebSockets for 2-way communication with embedded devices.

After some research, I found that there's a problem that needs to be solved for that: Clients need to choose which protocol to use, HTTP2 or HTTP1.1. As far as I see, there's several ways to achieve that:

1. Use Alt-Svc header in HTTP1.1 from uWebSockets. This actually isn't best solution, because even if client supports HTTP2, it may decide to not upgrade, and at least initial request will be done on HTTP1.1. Also, most likely would be needed to set up nghttp2 to listen on different port
2. Use ALPN. This is already used in HTTP2, but I don't really know how uWebSockets handle this and is this needed at all in HTTP1.1

WebSocket is upgraded from HTTP1.1, so it wouldn't be possible to getting rid of that at all.

Mostly, this is question about how it may be done in terms of uWebSockets. Any ideas/info?