private void processDelete(RowData row, RequestIndexer indexer) {
        final String key = createKey.apply(row);
        final DeleteRequest deleteRequest =
                requestFactory.createDeleteRequest(indexGenerator.generate(row), docType, key);
        indexer.add(deleteRequest);
    }
Sink function for converting upserts into Elasticsearch {@link ActionRequest}s.
inlong-sort/sort-flink/sort-flink-v1.18/sort-connectors/elasticsearch-base/src/main/java/org/apache/inlong/sort/elasticsearch/table/RowElasticsearchSinkFunction.java