Redis [Feature Request] - single active consumer abstraction

Hello and thank you to the Redis team.

This is a feature request to make it easier to implement "single active consumer" style message queues in Redis. Perhaps this could be treated as an extension to streams & consumer groups? It is my understanding that in order to insure single active consumer in Redis, you must generally implement your own additional locking around the list or stream. This causes a fair amount of overhead and complexity in the application. It would be great if there was a way to insure this semantic within the Redis server. For example, maybe a property such as "maxPending" on a consumer group that could be set to 1. Thanks for your consideration.