if(log.isInfoEnabled()) log.info("socket closed");
if(log.isDebugEnabled()) log.debug("socket closed");
    void closeSocket() {        if(sock != null) {            // by sending a dummy packet, the thread will terminate (if it was flagged as stopped before)            sendDummyPacket(sock.getLocalAddress(), sock.getLocalPort());            sock.close();            sock=null;             if(log.isInfoEnabled()) log.info("socket closed");        }    }