目前Apache Beam的PubSubIO写入并不支持setDelayThreshold()命令。不过，可以使用带有PubsubMessageEvent.RECEIVED_TIMESTAMP属性的消息对象来手动实现延迟处理。以下是示例代码：

import org.apache.beam.sdk.io.gcp.pubsub.PubsubMessage;
import org.joda.time.Duration;
import java.util.concurrent.TimeUnit;

// 创建一个PubsubMessage对象并添加RECEIVED_TIMESTAMP属性
PubsubMessage message = new PubsubMessage(payload, attributes);
message.setAttribute("PubsubMessageEvent.RECEIVED_TIMESTAMP",
    Long.toString(System.currentTimeMillis()));

// 在PubSubIO写入期间设置延迟时间
pipeline
  .apply("Write to Pub/Sub", PubsubIO.writeMessages()
    .withProjectId("my_project")
    .withTopic("my_topic")
    .withIdAttribute("id")
    .withTimestampAttribute("timestamp"))
  .withTimestampAttribute("PubsubMessageEvent.RECEIVED_TIMESTAMP")
  .withMethod(PubsubIO.Write.Method.BATCHING)
  .withBatchingSettings(PubsubIO.Write.BatchingSettings.newBuilder()
    .setDelayThreshold(Duration.standardSeconds(30))
    .setRequestBytesThreshold(1024 * 1024)
    .setElementCountThreshold(100)
    .build())

// 使用PubSubIO读取数据时也需要使用时间戳属性
pipeline.apply(PubsubIO.readMessages().fromTopic("my_topic")
    .withTimestampAttribute("PubsubMessageEvent.RECEIVED_TIMESTAMP")
    .withIdAttribute("id"))

这样，在写入消息到Pub/Sub时，将使用RECEIVED_TIMESTAMP属性来指定消息的时间戳，并设置延迟时间。在读取数据时，也需要使用相应的时间戳属性来确保正确处理延迟消息。