Direct byte buffer implementation for Hash

Includes implementations for SHA-256, SHA-512 and BLAKE2.
The name of this method made me a bit confuse about the idea here. If I understood correctly this method is unsafe because the buffer will be copied right?

And technically this method can be considered safe https://github.com/abstractj/kalium/pull/22/files#diff-b954966b8e38c3e220495517ad87f414R59, right? I'm asking because is confuse the idea of a safe method using an unsafe one.

Does my question make sense to you or I just added more confusion? :)