@Override
  protected Function<TypeDescription, OrcRowReader<?>> getOrcReaderFunction(
      Schema projectSchema, Map<Integer, ?> idToConstant) {
    return fileSchema -> new FlinkOrcReader(projectSchema, fileSchema, idToConstant);
  }
This is an mixed-format table reader accepts a {@link FileScanTask} and produces a {@link
CloseableIterator<RowData>}. The RowData read from this reader may have more columns than the
original schema. The additional columns are added after the original columns, see {@link
DeleteFilter}. It shall be projected before sent to downstream. This can be processed in {@link
DataIterator#next()}
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/read/source/FlinkUnkyedDataReader.java