pub fn is_valid_rfc3339(s: &str) -> boolExpand description
Return true when s is a complete RFC 3339 date-time, such as
2026-02-14T10:30:00Z or 2026-02-14T10:30:00.5+08:00.
Composed from is_valid_rfc3339_date and is_valid_rfc3339_time: a
full-date, a T/t separator, a partial-time (with optional fractional
seconds), and a mandatory time-offset — either Z/z or ±HH:MM with
HH in 00..23 and MM in 00..59. The offset is required, so a bare
2026-02-14T10:30:00 is rejected; a space separator is rejected (only T/t
is accepted); and a leap second (:60) is rejected, matching
is_valid_rfc3339_time. Non-ASCII input is rejected.