At the moment, rust-asn1 supports IMPLICIT and EXPLICIT tags via const generics on the Implicit and Explicit types, e.g.:

pub struct Implicit<T, const TAG: u32>

This makes the current APIs difficult to use in "dynamic" contexts, i.e. where the implicit/explicit tag value isn't known until runtime.

One possible solution here would be ImplicitDyn/ExplicitDyn (terrible names, please bikeshed) that take the tag at runtime instead but otherwise behave identically to the current Implicit and Explicit types.

Related to pyca/cryptography#12283.

CC @facutuesca