fn handle_goaway()

in neqo-http3/src/connection_client.rs [1173:1228]
50 lines of code
7 McCabe index (conditional complexity)

    fn handle_goaway(&mut self, goaway_stream_id: StreamId) -> Res<()> {
        qinfo!("[{self}] handle_goaway {goaway_stream_id}");

        if goaway_stream_id.is_uni() || goaway_stream_id.is_server_initiated() {
            return Err(Error::HttpId);
        }

        match self.base_handler.state {
            Http3State::Connected => {
                self.base_handler.state = Http3State::GoingAway(goaway_stream_id);
            }
            Http3State::GoingAway(ref mut stream_id) => {
                if goaway_stream_id > *stream_id {
                    return Err(Error::HttpGoaway);
                }
                *stream_id = goaway_stream_id;
            }
            Http3State::Closing(..) | Http3State::Closed(..) => {}
            _ => unreachable!("Should not receive Goaway frame in this state"),
        }

        // Issue reset events for streams >= goaway stream id
        let send_ids: Vec<StreamId> = self
            .base_handler
            .send_streams
            .iter()
            .filter_map(id_gte(goaway_stream_id))
            .collect();
        for id in send_ids {
            // We do not care about streams that are going to be closed.
            drop(self.base_handler.handle_stream_stop_sending(
                id,
                Error::HttpRequestRejected.code(),
                &mut self.conn,
            ));
        }

        let recv_ids: Vec<StreamId> = self
            .base_handler
            .recv_streams
            .iter()
            .filter_map(id_gte(goaway_stream_id))
            .collect();
        for id in recv_ids {
            // We do not care about streams that are going to be closed.
            drop(self.base_handler.handle_stream_reset(
                id,
                Error::HttpRequestRejected.code(),
                &mut self.conn,
            ));
        }

        self.events.goaway_received();

        Ok(())
    }