Why use service bus queue and topic instantly.

With the help of service bus queue and topic, we can

1. Decouple client and server applications
2. Implement fire and forget easily
3. Increase performance of client application, by using various performance optimization technique like prefetching.
4. Easily scale client and server application independent of each other
5. Implement duplicate detection
6. Re-send failed messages using deadletter queue
7. Control traffic
8. Implement retry logic
9. Process a request even after 14 days

With service bus no request is lost. Request messages will stay in queue waiting to be picked up by server application for processing until server is available

Each message is locked so no other thread can process the message. Lock duration can be configured

more on service bus here or here