Macro register 

register!() { /* proc-macro */ }

Registers #[command] functions with a package builder.

use rustra::prelude::*;

#[bridge_type]
struct AddInput { a: i64, b: i64 }
#[bridge_type]
struct AddOutput { sum: i64 }

#[command]
fn add_numbers(input: AddInput) -> Result<AddOutput> {
    Ok(AddOutput { sum: input.a + input.b })
}

let pkg = rustra::register!(Package::builder("my.pkg"), add_numbers).build();