in flink-connector-opensearch/src/main/java/org/apache/flink/streaming/connectors/opensearch/OpensearchSink.java [692:699]
public void setBulkFlushInterval(long intervalMillis) {
Preconditions.checkArgument(
intervalMillis == -1 || intervalMillis >= 0,
"Interval (in milliseconds) between each flush must be larger than or equal to 0.");
this.bulkRequestsConfig.put(
CONFIG_KEY_BULK_FLUSH_INTERVAL_MS, String.valueOf(intervalMillis));
}