This module implements displaying ClockTime as a String which does NOT depend on the time-zone.
Convert a ClockTime to a String. This has the format <optional sign><digits>+<digits> where the digits encode two integers N1 and N2 (in order) representing the time elapsed since 00:00:00 UTC on 1 Jan 1970. This will be N1 + (N2 / 10^12) seconds. 0<=N2<10^12.