span

calculate

• spanMs: Return the exact elapsed milliseconds between two ISO 8601 instant strings.
• spanNs: Return the exact elapsed nanoseconds between two ISO 8601 instant strings.
• spanWallClock: Return the wall-clock distance between two zoned datetime strings — calendar time, not elapsed time.

validate

• isValidSpan: Validate whether two ISO 8601 instant strings form a measurable span.