use std::io; use crate::{Sign, Time, SPACE}; impl Time {    /// Serialize this instance to `out` in a format suitable for use in header fields of serialized git commits or tags.    pub fn write_to(&self, mut out: impl io::Write) -> io::Result<()> {        itoa::write(&mut out, self.time)?;        out.write_all(SPACE)?;        out.write_all(&[match self.sign {            Sign::Plus => b'+',            Sign::Minus => b'-',        }])?;         const ZERO: &[u8; 1] = b"0";         const SECONDS_PER_HOUR: i32 = 60 * 60;        let offset = self.offset.abs();        let hours = offset / SECONDS_PER_HOUR;        assert!(hours < 25, "offset is more than a day: {}", hours);        let minutes = (offset - (hours * SECONDS_PER_HOUR)) / 60;         if hours < 10 {            out.write_all(ZERO)?;        }        itoa::write(&mut out, hours)?;         if minutes < 10 {            out.write_all(ZERO)?;        }        itoa::write(&mut out, minutes).map(|_| ())    }}