func (listener *CarbonlinkListener) Addr() net.Addr {
	if listener.tcpListener == nil {
		return nil
	}
	return listener.tcpListener.Addr()
}
func (listener *CarbonlinkListener) Addr() net.Addr {
	if listener.tcpListener == nil {
		return nil
	}
	return listener.tcpListener.Addr()
}
// Addr returns binded socket address. For bind port 0 in tests