public File getWALFile(long versionId) throws FileNotFoundException {
    return WALFileUtils.getWALFile(logDirectory, versionId);
  }
Get the .wal file starts with the specified version id
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/node/WALNode.java