Derive Macro Unit 

#[derive(Unit)]
{
    // Attributes available to this derive:
    #[unit]
}

Derive macro used by qtty-core to define unit marker types.

This macro expands in terms of crate::Unit and crate::Quantity, so it is intended for use inside qtty-core (or crates exposing the same crate-root API). Most users should not need this. Derive crate::Unit and a Display impl for crate::Quantity<ThisUnit>.

The derive must be paired with a #[unit(...)] attribute providing symbol, dimension, and ratio.

This macro is intended for use by qtty-core.