Think hard about how to handle CHOICE

[alex]

No description provided.

[alex]

Fundamentally the only possible API here is:

• Peek at tag
• give that to callback, let it do stuff

Implementation is straightforward pending figuring out implicit/explicit tagging

[alex]

I think you can basically treat a choice as a sequence of optionals (possibyl with explicit/implicit tags) where at least one must have a value.

[alex]

Ok, better plan:

enum Choice2<T1: Asn1Element, T2: Asn1Element> {
    Element1(T1::Output),
    Element2(T2::Output),
}

we can generate 2-5 of these or so.

[alex]

This worked out easily enough, solved in #54