I was recently hacking on rust-postgres, and it is using bytes::Bytes and BytesMut. But then it's also makes its own buffer type, and it also uses &[u8] some places. And the bytes crate also offers Buf and BufMut.
I'm getting a little lost in what types I should be using for network programming and similar tasks. Are there general rules about when I should be using which types?
&[u8] is the lowest common denominator for exposing bytes. You can't store any data as a slice, only temporarily view data stored elsewhere through a slice.
My understanding is that Bytes is a fancy version of Arc<[u8]>. I've never needed it. Vec<u8> usually is good enough for me.
Tangentially, you may find the bstr crate useful for performing String-like operations on byte buffers which may not be UTF8 (such as various networking protocols).