Macro fatal 

macro_rules! fatal {
    ($msg:expr) => { ... };
    ($msg:expr, $err:expr) => { ... };
}

Logs a message at the fatal level, with optional error details.

use narlog::prelude::*;
use std::io;
use std::io::ErrorKind;

let error = io::Error::new(ErrorKind::Other, "velit esse cillum dolore eu fugiat nulla pariatur");
fatal!("Duis aute irure dolor in reprehenderit in voluptate");
fatal!("Duis aute irure dolor in reprehenderit in voluptate", &error); // with error