private void configureFlushInterval(BulkProcessor.Builder bulkProcessorBuilder) {
        if (bulkProcessorFlushIntervalMillis == -1) {
            bulkProcessorBuilder.setFlushInterval(null);
        } else {
            callBridge.configureBulkProcessorFlushInterval(
                    bulkProcessorBuilder, bulkProcessorFlushIntervalMillis);
        }
    }
Build the {@link BulkProcessor}.

<p>Note: this is exposed for testing purposes.
inlong-sort/sort-flink/sort-flink-v1.15/sort-connectors/elasticsearch-base/src/main/java/org/apache/inlong/sort/elasticsearch/ElasticsearchSinkBase.java