private static ClusterKey buildClusterKey(AgentInfo info) {
        Objects.requireNonNull(info, "info");
        return new ClusterKey(info.getApplicationName(), info.getAgentId(), info.getStartTimestamp());
    }
@author HyunGil Jeong
@author Taejin Koo
web/src/main/java/com/navercorp/pinpoint/web/service/AgentServiceImpl.java