Enable an application to announce events to multiple interested consumers asynchronously, without coupling the senders to the receivers : https://docs.microsoft.com/en-us/azure/architecture/patterns/publisher-subscriber
Context and problem
Avoid the sender to wait for a response and avoid the consumer to know the identity of the producer.Solution
Pus/Sub Messaging Pattern
Challenges
The channels in a publish-subscribe system are treated as unidirectional. If a specific subscriber needs to send acknowledgment or communicate status back to the publisher, consider using the Request/Reply Pattern. This pattern uses one channel to send a message to the subscriber, and a separate reply channel for communicating back to the publisher.