1. I read an article about the challenges with regards to filtering real time events to a client view when sending push data, on the blog of small startup doing real-time infrastructure SaaS. It was a very informative article upvoted on Hacker News. I am interested in a link to this article as I am unable to find it. In addition, I have the following questions:

2. What are the patterns or best practices documentation(s) regarding subscribing clients to events and dispatching the correct events to particular clients in async web socket server?

In the context of:
1. Interesting or favorable libraries to accomplish real time dispatching patterns.
2. Performance considerations.