@Override
  public String toString() {
    return "BusyRegionSplitPolicy{" + "maxBlockedRequests=" + maxBlockedRequests + ", minAge="
      + minAge + ", aggregationWindow=" + aggregationWindow + ", " + super.toString() + '}';
  }
This class represents a split policy which makes the split decision based on how busy a region
is. The metric that is used here is the fraction of total write requests that are blocked due to
high memstore utilization. This fractional rate is calculated over a running window of
"hbase.busy.policy.aggWindow" milliseconds. The rate is a time-weighted aggregated average of the
rate in the current window and the true average rate in the previous window.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/BusyRegionSplitPolicy.java