@Override
  public void postMasterStartupInitialize() {
    if (provider != null && regionFinder != null) {
      regionFinder.refreshAndWait(provider.getAssignedRegions());
    }
  }
This Constructor accepts an instance of MetricsBalancer, which will be used instead of creating
a new one
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java