You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: input.rs
    path of file: ./repos/termion/src
    
    the code of the file until where you have to start completion: //! User input.

use std::io::{self, Read, Write};
use std::ops;
use std::os::fd::AsFd;

use event::{self, Event, Key};
use raw::IntoRawMode;

/// An iterator over input keys.
pub struc
    
    fn test_function_keys() {
        let mut st = b"\x1BOP\x1BOQ\x1BOR\x1BOS".keys();
        for i in 1..5 {
            assert_eq!(st.next().unwrap().unwrap(), Key::F(i));
        }

        let mut st = b"\x1B[11~\x1B[12~\x1B[13~\x1B[14~\x1B[15~\
        \x1B[17~\x1B[18~\x1B[19~\x1B[20~\x1B[21~\x1B[23~\x1B[24~"
            .keys();
        for i in 1..13 {
            assert_eq!(st.next().unwrap().unwrap(), Key::F(i));
        }
    }