code: public static UniqueIds createUids(Configuration conf) {
          UniqueId usid = new UniqueId(SID_TABLE, SID_WIDTH, conf, true);
          UniqueId uiid = new UniqueId(IID_TABLE, IID_WIDTH, conf, true);
          UniqueId upid = new UniqueId(PID_TABLE, PID_WIDTH, conf, true);
          return new UniqueIds(uiid, usid, upid);
      }
docs: Create the unique lookup tables.
  @param conf HBase configuration.
  @return a holder for sid and iid lookup.