extern crate chrono; // 0.4.4


use std::time::{
    Duration,
    SystemTime,
    UNIX_EPOCH,
};

use chrono::{
    DateTime,
    Utc,
};

fn format_iso8601(ts: SystemTime) -> String {
    let fmt = DateTime::<Utc>::from(ts).format("%Y-%m-%dT%H:%M:%S%.6fZ");
    format!("{}", fmt)
}

fn main() {
    println!("{}", format_iso8601(UNIX_EPOCH));
    println!("{}", format_iso8601(SystemTime::now()));
    println!("{}", format_iso8601(UNIX_EPOCH + Duration::new(8474622245848, 0)));
}