public void setHighSeqnoAt(Address sender, long high_seqno) { int index=getIndex(sender); if(index < 0) return;
public void setHighSeqnoAt(int index, long high_seqno) { if(index < size()) { high_seqnos[index]=high_seqno; }
    public void setHighSeqnoAt(Address sender, long high_seqno) {        int index=getIndex(sender);        if(index < 0)            return;        else            setHighSeqnoAt(index, high_seqno);    }