bytes 0.5 compatibility

[Fabian-Gruenbichler]

I'm currently in the process of updating packaged crates for futures 0.3/tokio 0.2 compatibility in Debian, which also entails updating to bytes 0.5.

Unfortunately bytes 0.4->0.5 does entail some breaking changes, and bcder's Captured/CapturedWriter are affected as well:

call in Captured::extend

error[E0599]: no method named `extend_from_slice` found for type `&'a mut bytes::bytes::Bytes` in the current scope
   --> src/captured.rs:197:16
    |
197 |         self.0.extend_from_slice(buf);
    |                ^^^^^^^^^^^^^^^^^ help: there is a method with a similar name: `clone_from_slice`

I am not sure whether this means that Captured needs to switch over to BytesMut or whether there is a simpler solution. tokio-rs/bytes#368 and tokio-rs/bytes#350 might also be related.

[partim]

Just switching to BytesMut won’t do, since then there will be lots of copying on cloning – Captured currently promises cheap copies. We might have to have a separate CapturedMut, but I need to look at the code that uses this stuff to see how awkward that would be.

[Fabian-Gruenbichler]

Obviously you know your code base better than me, and I am happy if I don't have to dig in further and can leave it in your hands instead :) it will probably take at least a few weeks until this actual starts to block anything on the Debian side, so no need to hurry (yet ;-) ).

[partim]

This is now solved via #43, #46, and #47.