public void setRestClientFactory(RestClientFactory restClientFactory) {
            this.restClientFactory = Preconditions.checkNotNull(restClientFactory);
        }
Sets a REST client factory for custom client configuration.

@param restClientFactory the factory that configures the rest client.
inlong-sort/sort-flink/sort-flink-v1.18/sort-connectors/elasticsearch7/src/main/java/org/apache/inlong/sort/elasticsearch7/ElasticsearchSink.java