public AgentInfoBo getSimpleAgentInfo(@NotBlank final String agentId, @PositiveOrZero final long timestamp) {
        return agentInfoDao.getSimpleAgentInfo(agentId, timestamp);
    }
@author emeroad
@author koo.taejin
@author jaehong.kim
collector/src/main/java/com/navercorp/pinpoint/collector/service/AgentInfoService.java