public static WALFileStatus valueOf(int code) {
    for (WALFileStatus status : WALFileStatus.values()) {
      if (status.code == code) {
        return status;
      }
    }
    return null;
  }
This enumeration class annotates the status of wal file. This first bit is used to denote whether
this contains search index.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/utils/WALFileStatus.java