for _, pcs := range tr.idleConn {
		for _, pc := range pcs {
			pc.conn.Close()
		}
	}
	tr.idleMu.Unlock()
}

// ResponseWriterConnForTesting returns w's underlying connection, if w
// is a regular *response ResponseWriter.
func ResponseWriterConnForTesting(w ResponseWriter) (c net.Conn, ok bool) {
	if r, ok := w.(*response); ok {
		return r.conn.rwc, true
	}
	return nil, false
}