for _, pc := range conns {
			ret = append(ret, pc.conn.LocalAddr().String()+"/"+pc.conn.RemoteAddr().String())
		}
	}
	slices.Sort(ret)
	return ret
}

func (t *Transport) IdleConnStrsForTesting_h2() []string {
	var ret []string
	noDialPool := t.h2transport.(*http2Transport).ConnPool.(http2noDialClientConnPool)
	pool := noDialPool.http2clientConnPool

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

		tr := cst.tr
		tr.IdleConnTimeout = timeout
		defer tr.CloseIdleConnections()
		c := &Client{Transport: tr}

		idleConns := func() []string {
			if mode == http2Mode {
				return tr.IdleConnStrsForTesting_h2()
			} else {
				return tr.IdleConnStrsForTesting()
			}
		}

		var conn string
		doReq := func(n int) (timeoutOk bool) {
			req, _ := NewRequest("GET", cst.ts.URL, nil)