@Override
    public String toString() {
        // FIXME temporarily hard-coded due to a change in the data structure
        return "AgentHistogram{" +
                "agent='" + agentId.getName() + '\'' +
                ", serviceType=" + agentId.getServiceType() +
                // FIXME temporarily hard-coded due to a change in the data structure
                ", " + timeHistogramMap +
                '}';
    }
to uniquely identify a host from UI, we can use things like hostname, agentId, endpoint, etc
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/rawdata/AgentHistogram.java