@Override
    public IndexedConsensusRequest next() {
      if (itr == null && !hasNext()) {
        throw new NoSuchElementException();
      }

      IndexedConsensusRequest request = itr.next();
      nextSearchIndex = request.getSearchIndex() + 1;
      return request;
    }
last broken wal file's version id
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/node/WALNode.java