private void processDelete(Row row, RequestIndexer indexer) {
			final String key = createKey(row);
			final DeleteRequest deleteRequest = requestFactory.createDeleteRequest(
				index,
				docType,
				key);
			indexer.add(deleteRequest);
		}
Sink function for converting upserts into Elasticsearch {@link ActionRequest}s.
elasticsearch5-xh/elasticsearch5-xh-sink/src/main/java/org/apache/flink/streaming/connectors/elasticsearch/ElasticsearchUpsertTableSinkBase.java