Tracing in a library

[package]
name = "demo-lib"
version = "0.1.0"
edition = "2024"

[dependencies]
tracing = "0.1"

#![allow(unused)]
fn main() {
use tracing::debug;

pub fn add(left: u64, right: u64) -> u64 {
    debug!(left, right, "add");
    left + right
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_works() {
        let result = add(2, 2);
        assert_eq!(result, 4);
    }
}
}