In upcoming releases 1.4.0 of Nexus Async Caller and 1.9.0 of Nexus Business Events, support for prioritized queues will be introduced. See Release plan.
In Nexus Async Caller
In a Nexus based platform, asynchronous requests are handled by the service Nexus Async Caller, which by default works with a queue of requests where a single request normally is handled within sub seconds.
However, when there are many systems involved, they can have different needs of prioity. If one system performs slowly for a while there is a risk of a growing queue. For some systems that are designed for this it's fine, but there might be other systems that need to be near real time.
The solution to this is to use prioritized queues in Async Caller, introducing multiple queues and multiple workers. When sending a request with Async Caller, you tell it which priority the request has and it is put on the corresponding queue.
This is setup in the configuration, see Configure Async Caller.
In Nexus Business Events
When publishing an event, Async Caller is used in the background. Based on it's support for prioritized queues, you can configure each subscription to an event to have a priority.
This is setup in the Business Events configuration, see Seeding Business Events.