public Map<String, ResponseTimeStatics> getAgentResponseStatisticsMap() {
        if (agentHistogramMap == null) {
            return Map.of();
        }
        Map<String, ResponseTimeStatics> map = new HashMap<>(agentHistogramMap.size());
        agentHistogramMap.forEach((agentId, histogram) ->
                map.put(agentId, ResponseTimeStatics.fromHistogram(histogram))
        );
        return map;
    }
this class is a collection of
applicationHistogram
agentHistogram
applicationTimeHistogram
agentTimeHistogram

@author emeroad
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/histogram/NodeHistogram.java