[QuinnWilton]

Yes, that's mostly it!

A lot of what I'm talking about has to do with configuration, but reuse is another big element. Your example has no configuration, and so is good in that regard, however your example is not reusable, in the sense that it's only possible for a single counter to exist.

I realize this is a contrived example, because you were trying to keep things simple, but if I needed two distinct atomic counters in my app, then I wouldn't be able to use Ergo, as it's currently implemented, because the application only starts a single counter, and doesn't provide any capabilities for starting additional counters.

You could change Ergo to get around this, possibly by instead running a dynamic supervisor that can start named counters under it, using something like `Ergo.create_counter/1`, but this would only address this specific use case.

To go back to my last comment, if you instead exposed, for example, a `__using__` macro that modules could use to define new counters, then callers would be able to integrate as many counters as they needed, whenever or however into their supervision tree as they required.

This ties back to the testing point too: if the process is a singleton, managed by the application, then you can only run one test against that process at a time in order to isolate the state for this tests, and you need to ensure you properly clean up that state between tests. Instead though, if the library allows you to start the processes yourself, then each test can use `start_supervised!` to start it's own isolated copy of the process, which will be linked to the test's process, and automatically cleaned up once the test finishes.