Sodium_fmt.GenerichashGenerichash defines formatters for types defined in Sodium.Generichash.
hash formats a hash in this fashion: (Generichash.hash AAAAAA==).
secret_key formats a secret_key in this fashion: (Generichash.secret_key AAAAAA==).
module type S = sig ... endBytes offers versions of each of the above formatters, which get their value from a bytes value.