Function humantime::format_rfc3339

pub fn format_rfc3339(system_time: SystemTime) -> Rfc3339Timestamp

Format an RFC3339 timestamp 2018-02-14T00:28:07Z

This function formats timestamp with smart precision: i.e. if it has no fractional seconds, they aren’t written at all. And up to nine digits if they are.

The value is always UTC and ignores system timezone.