Subscriber-Only: Today's episode is available only to subscribers. If you are a Point-Free subscriber you can access your private podcast feed by visiting https://www.pointfree.co/account.

---

It's incredible how easy `@Shared` makes it to persist complex data types to the file system, but currently it completely ruins our ability to test features that use it. Let's fix that, and we will also explore what it means to derive a small piece of shared state from a bigger piece of shared state.