How HTTP Requests Work
If the browser notices the server supports HTTP/2 it sets up a HTTP/2 session (with a handshake that involves a few roundtrips like what I described for DNS) and creates a new stream for this request. The browser then formats the request as HTTP/2 wire format bytes (binary format) and writes it to the HTTP/2 stream, which writes it to the HTTP/2 framing layer, which writes it to the encryption layer, which writes it to the network socket and sends it over the internet.
Fascinating look at all that’s happening to merely visit something like website.com. To be quite honest, it’s incredible any of it even works at all.