Also support ToPrimitive

[daschl]

Hi!

I think adding ToPrimitive implementations would be a great benefit. Very often I need to convert to and from an enum with primitives. Do you think you can also add this implementation? Otherwise right now I can use your macro but then need to go implement ToPrimitive on my own :)

I'm new to rust and macro programming, so I don't know if I can pull it off easily. Let me know what you think!

[chrivers]

I have the same problem - I'm also not sure what to do. I think this should definitely be supported. I'll see if I can figure out a PR.

[cardoe]

fwiw, https://crates.io/crates/enum-primitive-derive supports ToPrimitive.