in flink-connector-gcp-pubsub/src/main/java/org/apache/flink/streaming/connectors/gcp/pubsub/PubSubSource.java [326:329]
public PubSubSourceBuilder<OUT> withMessageRateLimit(int messagePerSecondRateLimit) {
this.messagePerSecondRateLimit = messagePerSecondRateLimit;
return this;
}