fun DateRange.toInstantIntervalAt(zone: TimeZone): InstantInterval
Converts this range to an InstantInterval between the start of the first day and the end of the last day in zone.
fun DateTimeInterval.toInstantIntervalAt(zone: TimeZone): InstantInterval
Converts this interval to an InstantInterval where both endpoints are in zone.
Due to daylight savings time transitions, there a few complexities to be aware of. If the local time of either endpoint falls within a gap (meaning it doesn't exist), it will be adjusted forward by the length of the gap. If it falls within an overlap (meaning the local time exists twice), the earlier offset will be used.