Extremely fast loop unrolled fizz buzz

fizz.rs

use std::io::{self, Write};

fn main() {
    const BUFFER_CAPACITY: usize = 64 * 1024;
    let stdout = io::stdout();
    let handle = stdout.lock();
    let mut handle = io::BufWriter::with_capacity(BUFFER_CAPACITY, handle);
    let mut i: usize = 0;
    loop {
        i += 1;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\n").unwrap();
        i += 1;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\nFizz\n").unwrap();
        i += 2;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\nBuzz\nFizz\n").unwrap();
        i += 3;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\n").unwrap();
        i += 1;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\nFizz\nBuzz\n").unwrap();
        i += 3;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\nFizz\n").unwrap();
        i += 2;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\n").unwrap();
        i += 1;
        itoap::write(&mut handle, i).unwrap();
        handle.write(b"\nFizzBuzz\n").unwrap();
        i += 1;
    }
}