int getNumRegionsAdded() {
      return numRegionsAdded;
    }
Stores additional per-server information about the regions added/removed during the run of the
balancing algorithm.
</p>
For servers that shed regions, we need to track which regions we have already shed.
<b>nextRegionForUnload</b> contains the index in the list of regions on the server that is the
next to be shed.
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/SimpleLoadBalancer.java