I can also add a supplementary chapter explaining how it works under the hood. You’re correct about `ActorModel`: its a reusable model of actor system semantics

I can also add a supplementary chapter explaining how it works under the hood. You’re correct about `ActorModel`: its a reusable model of actor system semantics parameterized by an `Actor` implementation. Its “dual” is the `spawn` function that lets you run that same `Actor` implementation on a real network.