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: datetime_format.rs
    path of file: ./repos/phaser/phaser/vendor/humantime/benches
    
    the code of the file until where you have to start completion: #![feature(test)]
extern crate test;

use std::io::Write;
use std::time::{Duration, UNIX_EPOCH};

use humantime::format_rfc3339;

#[bench]
fn rfc3339_humantime_seconds(b: &mut test::Bencher) {
    let time = UNIX_EPOCH + Duration::new(1_483_228_799, 0);
    let mut buf = Vec::with_capacity(100);
    b.iter(|| {
        buf.truncate(0);
        write!(&mut buf, "{}", format_rfc3339(time)).unwrap()
    });
}

#[bench]
fn rfc3339_chrono(b: &mut test::Bencher) {
    use chrono::{DateTime, NaiveDateTime, Utc};
    use chrono::format::Item;
    use chrono::format::Item::*;
    use chrono::format::Numeric::*;
    use chrono::format::Fixed::*;
    use chrono::format::Pad::*;

    let time = DateTime::<Utc>::from_utc(
        NaiveDateTime::from_timestamp(1_483_228_799, 0), Utc);
    let mut buf = Vec::with_capacity(100);

    // formatting code from env_logger
    const ITEM
    
fn rfc3339_chrono(b: &mut test::Bencher) {
    use chrono::{DateTime, NaiveDateTime, Utc};
    use chrono::format::Item;
    use chrono::format::Item::*;
    use chrono::format::Numeric::*;
    use chrono::format::Fixed::*;
    use chrono::format::Pad::*;

    let time = DateTime::<Utc>::from_utc(
        NaiveDateTime::from_timestamp(1_483_228_799, 0), Utc);
    let mut buf = Vec::with_capacity(100);

    // formatting code from env_logger
    const ITEMS: &[Item<'static>] = {
        &[
            Numeric(Year, Zero),
            Literal("-"),
            Numeric(Month, Zero),
            Literal("-"),
            Numeric(Day, Zero),
            Literal("T"),
            Numeric(Hour, Zero),
            Literal(":"),
            Numeric(Minute, Zero),
            Literal(":"),
            Numeric(Second, Zero),
            Fixed(TimezoneOffsetZ),
        ]
    };


    b.iter(|| {
        buf.truncate(0);
        write!(&mut buf, "{}", time.format_with_items(ITEMS.iter().cloned()))
            .unwrap()
    });
}