public void setDeleted(boolean deleted) {
    this.deleted = deleted;
  }
This class encapsulates {@link IWALBuffer} and {@link CheckpointManager}. If search is enabled,
the order of search index should be protected by the upper layer, and the value should start from
1.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/node/WALNode.java