API usage and confusion

[hannesm]

Hey,

I'm not entirely sure I understand the API design. We have two types, ctx and t -- but what is the fundamental difference?

A ctx we can create by either empty or init -- hold on, should the ctx returned by empty be immutable or better not being used?

A t we receive from get, but also from the functions that take care of computing the hash of a string / string list /...

Now, the nicely introduced get_into_bytes is defined on ctx, so if I computed the hash with digest_string, I can't extract it into an existing byte vector.

Would it be possible to simplify the API and only provide a single type t? Since it is private anyways, I'd expect no issues... What do you think?