WebTransport: Add WebTransport as a new transport

[thernstig]

Is your feature request related to a problem? Please describe.
WebTransport (https://developer.mozilla.org/en-US/docs/Web/API/WebTransport) is a new HTTP/3 protocol that promises even faster connection time and solving various issues with WebSockets.

It would be cool if socket.io could transparently start implementing webtransport as a new transport option. Still keeping the same nice fallback mechanism that exists today between WebSockets and HTTP long-polling.

Describe the solution you'd like
Add a new transports option useable in client initialization: https://socket.io/docs/v3/client-initialization/#transports

Describe alternatives you've considered
Using WebTransport directly without socket.io. But that completely misses the cool API that socket.io provides.

[darrachequesne]

Hi! @thernstig ! This is indeed on our radar. Adding this transport on the client-side should be quite straightforward, but the server will require a bit more work.

Related:

• Node.js: HTTP/3 support nodejs/node#38478
• Deno: QUIC & HTTP/3 support denoland/deno#1558

µWebSockets.js does already support HTTP/3 though: https://github.com/uNetworking/uWebSockets/releases/tag/v20.16.0

[thernstig]

@darrachequesne that is great. I could not find an issue, hence why I created one. Looking forward to it in the future!

[darrachequesne]

Support for WebTransport has been added in 7195c0f, released in 6.5.0.

We will publish a new version of the socket.io-client package soon.

Thanks for the heads-up! 👍

[thernstig]

Now if only Safari could get with the program: https://caniuse.com/webtransport