consider a type state builder

[cgwalters]

derive-builder requires unwrap() and does runtime checks. There's a few popular crates that use type state, e.g.:

• https://lib.rs/crates/typed-builder
• https://lib.rs/crates/bon

I don't have experience with either, but I definitely don't like the pervasive requirement for unwrap() we have here.

[ariel-miculas]

I wonder if we can have multiple builders so we don't introduce a breaking change.

[cgwalters]

This one is definitely still relevant, as the unwrap() is something I think both humans and AI code review can and do flag.

I played with https://lib.rs/crates/bon a bit in another project and it seemed decent and is actively maintained. It also has some nontrivial reverse dependencies.

[cgwalters]

I wonder if we can have multiple builders so we don't introduce a breaking change.

Yeah, breaking changes are a bit annoying. That said, we apparently just did one here for something really minor (ref #276 )...and probably should have either considered making that an alternative API or - better - rolling it in with other semver breaking changes.

Anyways though I think the ergonomic improvements are big enough here that it makes sense.