public Object get(RowData struct, int index) {
        return this.fieldGetter[index].getFieldOrNull(struct);
    }
used in iceberg running in {@link SWITCH_APPEND_UPSERT_ENABLE}
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/iceberg/src/main/java/org/apache/inlong/sort/iceberg/schema/RowDataConverter.java