// Cargo.toml
chrono = { version = "0.4", features = ["serde", "rustc-serialize"] }

let mut date: DateTime<Utc> = DateTime::default();

date += Duration::years(1000); // no Duration::years()
date += Duration::months(1000); // no Duration::months()
date += Duration::days(1000); 
date += Duration::hours(1000); 
date += Duration::minutes(1000);
date += Duration::seconds(1000);

date = date.with_year(date.year() + 1000).unwrap(); // Ok
date = date.with_month(date.month() + 1000).unwrap(); // if date.with_month() parameter is over 12, panick

计算 rust eclipse 时间的Utc最好的方法是什么？？