人类使用的Duration包装器

std::time::Duration的包装器，用于处理人类可读形式的时间长度

DurationHuman

解析和格式化以进行人类交互

主要目标是声明一个从，以及格式化为，人类可读字符串的Duration。

解析字符串时，将所有带有时间单位的值加到总持续时间上，因此解析("1min 2s 1min")的结果为122s持续时间。

将字符串格式化为使用可以表示整数值的单位，因此122s的持续时间将格式化为122s，但86400s的持续时间将格式化为1天。

将字符串格式化为美观打印包括所有具有非零值的单位，因此122s将美观打印为"2min 2s"，而90060将打印为"1天 1小时 1分钟"。

# use duration_human::DurationHuman;
let duration = DurationHuman::try_from("80h").unwrap();
assert_eq!(format!("{:#}", duration), "3 days 8h".to_string());
assert_eq!(format!("{}", duration), "80h".to_string());
let duration = DurationHuman::try_from("72h").unwrap();
assert_eq!(format!("{:#}", duration), "3 days".to_string());
assert_eq!(format!("{}", duration), "3 days".to_string());
let duration = DurationHuman::try_from("18446744073709551615ns").unwrap();
assert_eq!(format!("{:#}", duration), "5 centuries 84 years 11 months 1 week 6 days 23h 34min 33s 709ms 551μs 615ns".to_string());
// precision is nano second
let duration = DurationHuman::try_from("604800μs").unwrap();
assert_eq!(format!("{:#}", duration), "604ms 800μs".to_string());
assert_eq!(duration.to_string(), "604800μs".to_string());
let duration = DurationHuman::try_from("604800ms").unwrap();
assert_eq!(format!("{:#}", duration), "10min 4s 800ms".to_string());
assert_eq!(duration.to_string(), "604800ms".to_string());
let duration = DurationHuman::try_from("604800s").unwrap();
assert_eq!(format!("{:#}", duration), "1 week".to_string());
let duration = DurationHuman::try_from("604800s").unwrap();
assert_eq!(format!("{:#}", duration), "1 week".to_string());
assert_eq!(format!("{}", duration), "1 week".to_string());
let duration = DurationHuman::try_from("608430s").unwrap();
assert_eq!(format!("{:#}", duration), "1 week 1h 30s".to_string());
assert_eq!(format!("{}", duration), "608430s".to_string());

添加到Instant

std::time::Instant支持Add，但我们不能在这里操作，所以我们将它反过来

use std::time::Instant;
use duration_human::{DurationHuman, DurationError};

let instant = Instant::now();
let duration = DurationHuman::try_from("420s")?;
let after = duration + instant;
let diff = DurationHuman::from(after - instant);
assert_eq!(format!("{}", diff), format!("7min"));