* http3: update documentation for `Hijacker`
The documentation for `Hijacker` seems to be legacy from
[v0.43.0](https://github.com/quic-go/quic-go/releases/tag/v0.43.0). This
commit updates the documentation to reflect the current API use.
* http3: update documentation for `HTTPStreamer`
The documentation for `HTTPStreamer` seems to be legacy from
[v0.43.0](https://github.com/quic-go/quic-go/releases/tag/v0.43.0). This
commit updates the documentation to reflect the current API use.
Currently the HTTPStreamer is implemented on the http.Request.Body. This
complicates usage, since it's not easily possible to flush the HTTP
header, requiring users to manually flash the header before taking over
the stream.
With this change, the HTTP header is now flushed automatically as soon
as HTTPStream is called.
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.
The http.Request.Body can be type-asserted to a http3.Settingser. The
Settings method on this interface blocks until the client's SETTINGS
frame has been received.
On the server side, the http.Request is consumed by the HTTP handler.
The HTTP handler may close the body (it doesn't have to though). In any
case, closing the stream is the wrong thing to do, since that closes the
write side of the stream. All we want to do is cancel the stream (if the
EOF hasn't been read yet).
