fmt.Fprintf(w, "Hello, %v", r.RemoteAddr)
	}))
	defer cst.close()

	var numOpen, numClose int32 // atomic

	tlsConfig := &tls.Config{InsecureSkipVerify: true}
	tr := &Transport{
		TLSClientConfig: tlsConfig,
		DialTLS: func(_, addr string) (net.Conn, error) {
			time.Sleep(10 * time.Millisecond)
			rc, err := net.Dial("tcp", addr)
			if err != nil {