Pretty Print Rust tracing Log Output

```cargo
[dependencies]
tracing = "0.1"
tracing-subscriber = "0.3"
```

use tracing::{Level, event, instrument};

#[instrument]
fn main() {
    let format = tracing_subscriber::fmt::format().pretty();
    tracing_subscriber::fmt()
      .event_format(format)
      .with_ansi(false)
      .with_max_level(Level::DEBUG)
      .init();
  event!(Level::INFO, "This is an info message");
  event!(Level::DEBUG, "This is a debug message");
}