The stream exposes two methods required for doing an HTTP request:
SendRequestHeader and ReadResponse. This can be used by applications
that wish to use the stream for non-HTTP content afterwards. This will
lead to a simplification in the API we need to expose for WebTransport,
and will make it easier to send HTTP Datagrams associated with this
stream.
* Fix protocol
The default value should be "HTTP/3.0".
* Reject normal request with :protocol header
The :protocol pseudo header is only defined for
Extended Connect requests (RFC 9220).
* save one branch check
* Fix review issue
