I think we should really stress here that the temporary buffer will be completly destroyed at the end of `ScopeBuffer`'s lifetime. It might seem "obvious", but you can never stress enough the unsafe things. In particular, I think most D coders now tend to forget about object lifetimes, what with the GC and all.

Also, adding a an example that, say, does a `return buf[].dup;` would be a good usage example.