This covers most of the commonly used `Uuid` and `UuidInterface` API, and allows us
to pass around `UuidInterface` references as if they were pure.
Note that this only verifies the *contract* of a `UuidInterface`: it is still very
much possible to write mutable `UuidInterface` implementations (and `Uuid` itself
has such an edge-case, allowing for replacement of the static `UuidFactory` reference),
but if you really do mutate UUIDs at runtime, then your code is very much hurting your
project, and you should get rid of that detail.
Marco Pivetta