An acknowledgment is a reply confirming that an asynchronous message was received or processed. Fire-and-forget delivery gives the sender no such confirmation, so the receiver must send one when confirmation matters. section 1.6.2 section 3.2.1
Use acknowledgments to distinguish observable outcomes from merely attempted sends:
- A successful reply provides evidence that the destination responded, but it does not make fire-and-forget delivery reliable. section 1.6.2 section 3.2.1
- A timeout indicates that no response arrived within the waiting period; the worker may have failed, replied too late, or become unreachable. section 3.2.1
- A message sent after the recipient stops is forwarded to dead letters rather than acknowledged by that recipient. section 3.2.1
Conversation and worker replies
A Conversation actor sends work asynchronously to a Mentions actor and continues. If it needs confirmation, Mentions sends an acknowledgment. In a manager–worker flow, a worker reply confirms completion; a missing reply produces a timeout, and later messages can appear in dead letters. section 1.6.2 section 3.2.1
Trace the intermediate actor's success, timeout, and post-timeout message behavior. section 3.2.1
