protected int moveForwardMostRecentPosition() {
    int index = ++mostRecent;
    if (!oneRound && index == getNumberOfStatistics()) {
      // Back to the head of the lastN, from now on will
      // start to evict oldest value.
      oneRound = true;
    }
    mostRecent = index % getNumberOfStatistics();
    return mostRecent;
  }
Move forward the most recent index.
@return the most recent index
hbase-common/src/main/java/org/apache/hadoop/hbase/util/WindowMovingAverage.java