@InterfaceAudience.Private
  public static byte[] createRegionEventDescriptorQualifier(RegionEventDescriptor.EventType t) {
    return Bytes.toBytes(REGION_EVENT_PREFIX_STR + t.toString());
  }
@return Cell qualifier for the passed in RegionEventDescriptor Type; e.g. we'll return
        something like a byte array with HBASE::REGION_EVENT::REGION_OPEN in it.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALEdit.java