testing webtransport

[lockphase]

Hi ! I'm trying to assess if my setup is ready for migration to webtransport, currently on websockets. I have a mockup dev server behind a nginx reverse proxy load balanced with pm2. Focusing on the client-side for now, the existing working codes are:

this.socket = io({
    transports: ["websocket"],
    query:some_token
});

I tested with below substitute

this.socket = io({
    transports: ["webtransport"],
    query:some_token
});

and found that
a) the webtransport opening handshake fails on https://my_domain/socket.io
b) the query token was never sent with the http3 request

Then I tested with another substitute

this.socket = io({
    transports: ["webtransport"],
    transportOptions: {
        webtransport: {
            hostname: "domain/sub/"
        }
    },
    query:{token:sessionStorage.getItem("token")}
});

and found that
c) the request becomes https://my_domain/sub/:433/socket.io
d) the query token was never sent with the http3 request

Just curious, how much of my findings are wai and which are bugs on my end? Are there any success stories with migrating to webtransport by the community?

Also, what if I want my clients to connect via websocket by default and upgrade to webtransport when needed, how should I go about it?