BufferType::SliceData should not take a Vec<u8> as parameter

[Gnurou]

Taking a Vec here means the client is likely to make an unneeded copy of the input data. Turning this parameter into a &[u8] means adding a lifetime parameter to the whole of BufferType...

Maybe the solution is to use the types of the members directly for Buffer::new, and remove BufferType altogether? This would need a new trait to obtain the (ptr, size) tuple but is probably cleaner.

[Gnurou]

Actually that sounds similar to issue #11 .