protected long getStatisticsAtIndex(int index) {
    if (index < 0 || index >= getNumberOfStatistics()) {
      // This case should not happen, but a prudent check.
      throw new IndexOutOfBoundsException();
    }
    return lastN[index];
  }
Get statistics at index.
@param index index of bar
hbase-common/src/main/java/org/apache/hadoop/hbase/util/WindowMovingAverage.java