docs: public void setAveragingPeriod(final int PERIOD) {
          if (null == averagingPeriod) {
              _averagingPeriod = PERIOD;
              movingAverage    = new MovingAverage(PERIOD); // MAX 1000 values
              fireUpdateEvent(REDRAW_EVENT);
          } else {
              averagingPeriod.set(PERIOD);
          }
      }