public JVMClusterUtil.RegionServerThread addRegionServer() throws IOException {
    return addRegionServer(new Configuration(conf), this.regionThreads.size());
  }
Constructor.
@param conf            Configuration to use. Post construction has the master's address.
@param noMasters       Count of masters to start.
@param noRegionServers Count of regionservers to start.
hbase-server/src/main/java/org/apache/hadoop/hbase/LocalHBaseCluster.java