@Override
    public RestHighLevelClient createClient(Map<String, String> clientConfig) {
        RestClientBuilder builder =
                RestClient.builder(httpHosts.toArray(new HttpHost[httpHosts.size()]));
        restClientFactory.configureRestClientBuilder(builder);
        RestHighLevelClient rhlClient = new RestHighLevelClient(builder);
        return rhlClient;
    }
The factory to configure the rest client.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/elasticsearch-6/src/main/java/org/apache/inlong/sort/elasticsearch6/Elasticsearch6ApiCallBridge.java