[LatticeAnimal]

That is a pretty compelling point... I ran into this less than an hour ago and was slightly frustrated.

Though, I still like the flexibility of adding additional fields to `Action1`. In golang I end up with fields that are conditionally populated based on the state of an Enum which is less than ideal and leads to lots of error checking (though this is relatively rare).

It doesn't have to be one or the other though. A bit more polishing on the Rust-style enums (perhaps in a different language) could lead to pretty ergonomic code.