private void listAllQueueIds(Table table, Scan scan, List<ReplicationQueueId> queueIds)
    throws IOException {
    try (ResultScanner scanner = table.getScanner(scan)) {
      for (;;) {
        Result result = scanner.next();
        if (result == null) {
          break;
        }
        ReplicationQueueId queueId = ReplicationQueueId.parse(Bytes.toString(result.getRow()));
        queueIds.add(queueId);
      }
    }
  }
HBase table based replication queue storage.
hbase-replication/src/main/java/org/apache/hadoop/hbase/replication/TableReplicationQueueStorage.java