code: public Service withDurationHistogram(HistogramEntry... durationHistogram) {
          if (this.durationHistogram == null) {
              setDurationHistogram(new java.util.ArrayList<HistogramEntry>(durationHistogram.length));
          }
          for (HistogramEntry ele : durationHistogram) {
              this.durationHistogram.add(ele);
          }
          return this;
      }
docs: <p>
  A histogram that maps the spread of service durations.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setDurationHistogram(java.util.Collection)} or {@link #withDurationHistogram(java.util.Collection)} if
  you want to override the existing values.
  </p>
  
  @param durationHistogram
  A histogram that maps the spread of service durations.
  @return Returns a reference to this object so that method calls can be chained together.