@Override
    public void notifyFinal(ReturnCode code, HRegionLocation loc, long heapSizeOfRow) {
      if (code == ReturnCode.INCLUDE) {
        regionsIncluded.add(loc.getRegion());
        serversIncluded.add(loc.getServerName());
      }
      busyRegions.add(loc.getRegion().getRegionName());
    }
1) check the regions is allowed. 2) check the concurrent tasks for regions. 3) check the
total concurrent tasks. 4) check the concurrent tasks for server.
@param loc           the destination of data
@param heapSizeOfRow the data size
@return either Include {@link RequestController.ReturnCode} or skip
        {@link RequestController.ReturnCode}
hbase-client/src/main/java/org/apache/hadoop/hbase/client/SimpleRequestController.java