#[derive(KeyValuePair)]Expand description
Derives the KeyValuePair trait for a enum. Each variant need to
have a value field which becomes part of the value enum and all remaining fields become
part of the key.
Assuming the enum is called Abc it exposes AbcKey and AbcValue types for it too. The
key enum will have Debug, Clone, PartialEq, Eq, and Hash derived. The
value enum will have Debug and Clone derived. It’s expected that all fields
implement these traits.