public static Object[] getSplitKey(
            RowType splitBoundaryType, SourceRecord dataRecord, SchemaNameAdjuster nameAdjuster) {
        // the split key field contains single field now
        String splitFieldName = nameAdjuster.adjust(splitBoundaryType.getFieldNames().get(0));
        Struct key = (Struct) dataRecord.key();
        return new Object[]{key.get(splitFieldName)};
    }
Returns the start offset of the binlog split.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/mysql-cdc/src/main/java/org/apache/inlong/sort/cdc/mysql/source/utils/RecordUtils.java