@Override
    public String toString() {
        return "ApdexScore{" +
                "apdexScore=" + apdexScore +
                ", apdexFormula=" + apdexFormula +
                '}';
    }
<a href="https://en.wikipedia.org/wiki/Apdex">https://en.wikipedia.org/wiki/Apdex</a>
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/histogram/ApdexScore.java