Tracing demo

---

examples/tracing/demo/Cargo.toml

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

[dependencies]
tracing = "0.1"
tracing-subscriber = "0.3.0"

examples/tracing/demo/src/main.rs

use tracing::{Level, debug, info};
use tracing_subscriber::FmtSubscriber;

fn main() {
    // Set up a tracing subscriber that logs to stdout.
    let subscriber = FmtSubscriber::builder()
        .with_max_level(Level::TRACE)
        .finish();
    tracing::subscriber::set_global_default(subscriber).expect("setting default subscriber failed");

    // Emit some log messages.
    info!("hello world");

    let number_of_yaks = 3;
    debug!(number_of_yaks, "preparing to shave yaks");
}