@Override
    public String toString() {
        return toStringHelper(this).omitNullValues()
                                   .add("instanceId", instanceId)
                                   .add("hostName", hostName)
                                   .add("appName", appName)
                                   .add("appGroupName", appGroupName)
                                   .add("ipAddr", ipAddr)
                                   .add("vipAddress", vipAddress)
                                   .add("secureVipAddress", secureVipAddress)
                                   .add("port", port)
                                   .add("securePort", securePort)
                                   .add("status", status)
                                   .add("homePageUrlPath", homePageUrlPath)
                                   .add("homePageUrl", homePageUrl)
                                   .add("statusPageUrlPath", statusPageUrlPath)
                                   .add("statusPageUrl", statusPageUrl)
                                   .add("healthCheckUrlPath", healthCheckUrlPath)
                                   .add("healthCheckUrl", healthCheckUrl)
                                   .add("secureHealthCheckUrl", secureHealthCheckUrl)
                                   .add("dataCenterInfo", dataCenterInfo)
                                   .add("leaseInfo", leaseInfo)
                                   .add("metadata", metadata)
                                   .add("lastUpdatedTimestamp", lastUpdatedTimestamp)
                                   .add("lastDirtyTimestamp", lastDirtyTimestamp)
                                   .toString();
    }
Returns the last dirty timestamp of this instance.
eureka/src/main/java/com/linecorp/armeria/common/eureka/InstanceInfo.java