I discovered this while trying to figure out why #34986 was not passing tests involving websockets. Servo's websocket network integration diverges immediately from the normal Fetch implementation in

. This means we duplicate logic about HSTS upgrades, blocked ports, etc. in and miss out on changes to the base Fetch implementation.

We should update our integration to follow https://websockets.spec.whatwg.org/#concept-websocket-establish and only enter websocket-specific code in https://fetch.spec.whatwg.org/#http-network-fetch .