deadLetterTopic property

The name of an optional Pub/Sub Lite topic to publish messages that can not be exported to the destination.

For example, the message can not be published to the Pub/Sub service because it does not satisfy the constraints documented at https://cloud.google.com/pubsub/docs/publisher. Structured like: projects/{project_number}/locations/{location}/topics/{topic_id}. Must be within the same project and location as the subscription. The topic may be changed or removed.

Optional.