MIDI API?

[maximecb]

I'm interested in music and music software, so I think it could be fun to have a MIDI input/output API. Preferably low level with access to the raw MIDI message bytes. I don't want to have a hierarchy of objects representing every single message type 🚫

Ideally whatever Rust package we use for MIDI support should be an optional dependency to avoid making the build dependent on extra libraries. Not sure what are the options for Rust, especially if this is to be done in a way that's somewhat cross-platform, could use some recommendations!