Macro register_freight 

macro_rules! register_freight {
    ($freight: expr, $name: ident) => { ... };
}

A macro, which can be used to create a registry function easier

Example

dusk_api::register_freight!(MyFreight, my_reg_fn);
dusk_api::export_freight!("test", "0.1.0", my_reg_fn);

pub struct MyFreight;

impl Freight for MyFreight {
    // Your implementation here
}