@Override
  public ServerName getServerHoldingRegion(final TableName tn, byte[] regionName)
    throws IOException {
    int index = getServerWith(regionName);
    if (index < 0) {
      return null;
    }
    return getRegionServer(index).getServerName();
  }
Get the location of the specified region
@param regionName Name of the region in bytes
@return Index into List of {@link SingleProcessHBaseCluster#getRegionServerThreads()} of HRS
        carrying hbase:meta. Returns -1 if none found.
hbase-server/src/test/java/org/apache/hadoop/hbase/SingleProcessHBaseCluster.java