@Override
    protected List<String> getFieldOrder() {
      return Arrays.asList(
          "szAccessPath",
          "szItemID",
          "bActive",
          "hClient",
          "dwBlobSize",
          "pBlob",
          "vtRequestedDataType",
          "wReserved");
    }
We define the OPC DA Classes and interfaces here like C's .h file.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/connector/protocol/opcda/OpcDaHeader.java