A Little Explanation of Little's Law(twitter.com)

I recently read Concurrency in Go by Katherine Cox-Buday. In the “Queuing” section, there was a discussion of how we can use Little’s Law to predict our pipeline’s throughput, given sufficient sampling. I honestly wondered why I had not come across this simple idea before, after finishing that part. As I understand it, it can potentially be used in almost any situation where a queue is involved. Not just message queues, even things like physical queues. So I thought I’d write an intuitive explanation to help it stick and share the idea.