I don't think there's much to wrap your head around. It doesn't seem to. As far as I can tell, this commits its own version of the classic multithreading 101 er

I don't think there's much to wrap your head around. It doesn't seem to. As far as I can tell, this commits its own version of the classic multithreading 101 error of assuming you can make any data structure "thread-safe" by slapping some lock statements around all its getters and setters, or that some relative newcomers to functional programming commit when they believe that all you need to eliminate concurrency problems is the `state` monad, and proceed to Greenspun Haskell into an imperative language by littering it all over their code. The truth is, you can mitigate concurrency problems, but there's no way to eliminate them, and believing that you have is a great way to make them worse.