mu    *sync.Mutex
	conns map[string][]*http2clientConn
}

type http2clientConn struct{}

type http2clientConnIdleState struct {
	canTakeNewRequest bool
}

func (cc *http2clientConn) idleState() http2clientConnIdleState { return http2clientConnIdleState{} }

func http2configureTransports(*Transport) (*http2Transport, error) { panic(noHTTP2) }

func http2isNoCachedConnError(err error) bool {

	pool := noDialPool.http2clientConnPool

	pool.mu.Lock()
	defer pool.mu.Unlock()

	for k, ccs := range pool.conns {
		for _, cc := range ccs {
			if cc.idleState().canTakeNewRequest {
				ret = append(ret, k)
			}
		}
	}

	slices.Sort(ret)
	return ret
}

func (t *Transport) IdleConnCountForTesting(scheme, addr string) int {
	t.idleMu.Lock()

// clientConnIdleState describes the suitability of a client
// connection to initiate a new RoundTrip request.
type http2clientConnIdleState struct {
	canTakeNewRequest bool
}

func (cc *http2ClientConn) idleState() http2clientConnIdleState {
	cc.mu.Lock()
	defer cc.mu.Unlock()
	return cc.idleStateLocked()
}

func (cc *http2ClientConn) idleStateLocked() (st http2clientConnIdleState) {