One of the patterns easily supported by the Azure Service Bus is the first-in-first-out (FIFO) pattern, which isn’t supported in the other queue service – Azure Storage Queues. To realise FIFO with the Azure Service Bus is to use sessions. Any service can create a session when sending a message to a queue or topic by setting the SessionId property. Subsequently, the session comes into existence when the queue or topic is session aware, which means you have specified ‘Enable session’ when creating the queue or topic.