deadLetterTopic property
The name of the topic to which dead letter messages should be published.
Format is projects/{project}/topics/{topic}.The Pub/Sub service account
associated with the enclosing subscription's parent project (i.e.,
service-{project_number}@gcp-sa-pubsub.iam.gserviceaccount.com) must have
permission to Publish() to this topic. The operation will fail if the
topic does not exist. Users should ensure that there is a subscription
attached to this topic since messages published to a topic with no
subscriptions are lost.
Optional.
Implementation
core.String? deadLetterTopic;