@Override
  public String toString() {
    return "WALEntryHandler{"
        + "memTableId="
        + memTableId
        + ", value="
        + value
        + ", walEntryPosition="
        + walEntryPosition
        + '}';
  }
Get this handler's value.

@throws WALPipeException when failing to get the value.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/utils/WALEntryHandler.java