code: protected void doFlush() {
          long[] values = unFlushed.getSnapshot().getValues();
          for (JHistogram histogram : histogramMap.values()) {
              for (long val : values) {
                  histogram.update(val);
              }
          }
          if (MetricUtils.metricAccurateCal) {
              for (long val : values) {
                  for (AsmMetric metric : this.assocMetrics) {
                      metric.updateDirectly(val);
                  }
              }
          }
          this.unFlushed = newHistogram();
      }
docs: flush temp histogram data to all windows & assoc metrics.