public org.apache.flink.table.descriptors.Elasticsearch bulkFlushInterval(long interval) {
		internalProperties.putLong(CONNECTOR_BULK_FLUSH_INTERVAL, interval);
		return this;
	}
Configures how to buffer elements before sending them in bulk to the cluster for efficiency.

<p>Sets the bulk flush interval (in milliseconds).

@param interval bulk flush interval (in milliseconds).
elasticsearch5-xh/elasticsearch5-xh-sink/src/main/java/org/apache/flink/table/descriptors/Elasticsearch.java