if(log.isInfoEnabled()) log.info("sending XMIT_REQ ([" + first_seqno + ", " + last_seqno + "]) to " + sender);
if(log.isDebugEnabled()) log.debug("sending XMIT_REQ ([" + first_seqno + ", " + last_seqno + "]) to " + sender);
    public synchronized void retransmit(long first_seqno, long last_seqno, Address sender) {        NakAckHeader hdr;        Message retransmit_msg=new Message(sender, null, null);        if(log.isInfoEnabled()) log.info("sending XMIT_REQ ([" + first_seqno +                ", " + last_seqno + "]) to " + sender);        //          //  if(log.isDebugEnabled()) log.debug("TRACE.special()", "XMIT: " + first_seqno + " - " + last_seqno + ", sender=" + sender);        //for(long i=first_seqno; i <= last_seqno; i++) {          //  addXmitRequest(sender, i);        //}        hdr=new NakAckHeader(NakAckHeader.XMIT_REQ, first_seqno, last_seqno);        retransmit_msg.putHeader(name, hdr);        passDown(new Event(Event.MSG, retransmit_msg));    }