@Override
    public String toString() {
        return "Histogram{" +
                "schema=" + schema +
                ", fastCount=" + fastCount +
                ", normalCount=" + normalCount +
                ", slowCount=" + slowCount +
                ", verySlowCount=" + verySlowCount +
                ", fastErrorCount=" + fastErrorCount +
                ", normalErrorCount=" + normalErrorCount +
                ", slowErrorCount=" + slowErrorCount +
                ", verySlowErrorCount=" + verySlowErrorCount +
                ", sumElapsed=" + sumElapsed +
                ", maxElapsed=" + maxElapsed +
                ", pingCount=" + pingCount +
                '}';
    }
@author emeroad
@author netspider
@author jaehong.kim
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/histogram/Histogram.java