如何在数据流管道中实现PubSubIO中的流量控制设置

import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.io.gcp.pubsub.PubsubIO;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.transforms.DoFn;
import org.apache.beam.sdk.transforms.ParDo;

public class PubSubFlowControlExample {
  public static void main(String[] args) {
    PipelineOptions options = PipelineOptionsFactory.fromArgs(args).create();
    Pipeline pipeline = Pipeline.create(options);

    pipeline
        .apply(
            "Read from PubSub",
            PubsubIO.readStrings().fromSubscription("projects/my-project/subscriptions/my-sub"))
        .apply(
            "Process data",
            ParDo.of(new DoFn<String, String>() {
              @ProcessElement
              public void processElement(ProcessContext c) {
                // Process the data here
                // Implement flow control logic if needed
                c.output(c.element());
              }
            }))
        .apply(
            "Write to PubSub",
            PubsubIO.writeStrings().toTopic("projects/my-project/topics/my-topic"));

    pipeline.run().waitUntilFinish();
  }
}