@Override
    public ClusterKey getClusterKey(String applicationName, String agentId, long startTimeStamp) {
        return getClusterKey(applicationName, agentId, startTimeStamp, false);
    }
@author HyunGil Jeong
@author Taejin Koo
web/src/main/java/com/navercorp/pinpoint/web/service/AgentServiceImpl.java