When receiving a GOAWAY frame, the client:
* immediately closes the connection if there are no active requests
* refuses to open streams with stream IDs larger than the stream ID in
the GOAWAY frame
* closes the connection once the stream count drops to zero
* http3: implement server idle timeout support
This update introduces the ability for an HTTP/3 server to enforce an idle
timeout on connections. This timeout will trigger when no new requests are
received on a connection, irrespective of any PING frames received at the
QUIC level.
* fix deadlock when http3 idle timeout is not enabled
* fix typo
* Switch to a more efficient implementation
* Avoid a goroutine
* Avoid constent re-adjusting of a timer
* Works with hijacked streams
* Generalize the idle timeout description
* Add an integration test for http server idle timeout
* Attempt to fix other tests impacted by the new idle timeout test
