@Override
    public void add(IndexRequest... indexRequests) {
        for (IndexRequest indexRequest : indexRequests) {
            if (flushOnCheckpoint) {
                numPendingRequestsRef.getAndIncrement();
            }
            this.bulkProcessor.add(indexRequest);
        }
    }
Implementation of a {@link RequestIndexer}, using a {@link BulkProcessor}. {@link ActionRequest
ActionRequests} will be buffered before sending a bulk request to the Elasticsearch cluster.

<p>Note: This class is binary compatible to Elasticsearch 7.
inlong-sort/sort-flink/sort-flink-v1.18/sort-connectors/elasticsearch7/src/main/java/org/apache/inlong/sort/elasticsearch7/Elasticsearch7BulkProcessorIndexer.java