@Override
                public Object read(
                        SourceRecord record, @Nullable TableChanges.TableChange tableSchema) {
                    if (tableSchema == null) {
                        return null;
                    }
                    return new GenericArrayData(
                            tableSchema.getTable().primaryKeyColumnNames().stream()
                                    .map(StringData::fromString)
                                    .toArray());
                }
The update-before data for UPDATE record.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/mysql-cdc/src/main/java/org/apache/inlong/sort/cdc/mysql/table/MySqlReadableMetadata.java