public void setFailureHandler(ActionRequestFailureHandler failureHandler) {
            this.failureHandler = Preconditions.checkNotNull(failureHandler);
        }
Sets a failure handler for action requests.

@param failureHandler This is used to handle failed {@link ActionRequest}.
inlong-sort/sort-flink/sort-flink-v1.18/sort-connectors/elasticsearch7/src/main/java/org/apache/inlong/sort/elasticsearch7/ElasticsearchSink.java