See this issue for motivation.

If user code fails to process a message due to transient failures in other services, the users might not want to make the message immediately available for redelivery. The message would just be quickly redelivered just to fail again.

One way we can help is providing a way to forget messages. The client library can stop extending the messages' deadline and let the messages redeliver naturally without spending time and memory keeping track of their ack IDs.

@jba @kamalaboulhosn WDYT?