Inspect the result of iron like below
``` rust let mut chain = Chain::new(handler); chain.linkafter(Inspect::new(|req, res| match res { Ok(r) => println!("ok: {:?}", r), Err(e) => println!("err: {:?}", e), })); chain.linkafter(Inspect::response( |req, res| println!("response: {:?}", res), ));
chain.linkafter(Inspect::error(|req, err| println!("error: {:?}", err))); ```