setHighSeqnoSeenAt(index, high_seqno_seen);
if(log.isErrorEnabled()) log.error("index " + index + " is out of bounds");
    public void setHighSeqnoSeenAt(Address sender, long high_seqno_seen) {        int index=getIndex(sender);        if(index < 0)            return;        else            setHighSeqnoSeenAt(index, high_seqno_seen);    }