Hello,
I recently appeared for an interview in Uber. The round was machine coding round and they asked me to build a system like kafka where we will have topics and multiple publishers and susbcribers should be able to interact with it without one blocking another. Idea was to think handle concurrent requests and use multi-threading so that all subscribers can run in parallel.

I have created a video on my solution. Posting it here as I think it can help others who are also preparing:

Also link for the repo where I have pushed my code:
https://github.com/anomaly2104/low-level-design-messaging-queue-pub-sub