@Override
    public void close() throws Exception {
        elasticsearchSinkFunction.close();
        if (bulkProcessor != null) {
            bulkProcessor.close();
            bulkProcessor = null;
        }
        if (client != null) {
            client.close();
            client = null;
        }
        callBridge.cleanup();
        // make sure any errors from callbacks are rethrown
        checkErrorAndRethrow();
    }
Disable flushing on checkpoint. When disabled, the sink will not wait for all pending action
requests to be acknowledged by Elasticsearch on checkpoints.

<p>NOTE: If flushing on checkpoint is disabled, the Flink Elasticsearch Sink does NOT provide
any strong guarantees for at-least-once delivery of action requests.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/elasticsearch-base/src/main/java/org/apache/inlong/sort/elasticsearch/ElasticsearchSinkBase.java