Call it what you will. The point about the handshake is that TCP + http headers need comes before the upgrade to use the raw tcp streams. This is part of the benchmark and while it exists also in the real world it can be misleading because that’s testing connections, not message throughput.

Also I was wrong about uWebSocket, they do have tls support so you can skip reverse proxy. It deals with raw tcp conns and thus to encrypt you need tls support there. It is also a barebones http/1.1 server because why not. The thing I misremembered is I confused tls with http/2 which it does not support. This is unrelated to WS.