Function format_time_wrt 

pub fn format_time_wrt(t: SystemTime, now: SystemTime) -> FormattedTime

Formats the given time in UTC using RFC3339 and, to aid interpretation, adds a human readable time delta.

Both time and time delta are rounded to seconds.

For example, at the time of writing the unix epoch is displayed thusly: 1970-01-01T00:00:00Z (2810w 13h 13m 23s ago)