QueueEntry(MessageAddress agent, long to, PingListener l) { this.agent = agent;
QueueEntry(String agentNames[], long to, PingListener l) { for (int i = 0; i < agentNames.length; i++) { agentsToPing.add(MessageAddress.getMessageAddress(agentNames[i])); }
    QueueEntry(MessageAddress agent, long to, PingListener l) {      this.agent = agent;      this.timeout = to;      this.listener = l;    }