OptionalbyDay-of-week specifications from BYDAY with optional nth occurrences
OptionalbyHour filters (0..23) from BYHOUR
OptionalbyMinute filters (0..59) from BYMINUTE
OptionalbyFilter months (1..12) from BYMONTH
OptionalbySet position selectors from BYSETPOS
OptionalcountMaximum number of occurrences to generate, if bounded by COUNT
Frequency unit: DAILY, WEEKLY, MONTHLY, or YEARLY
Inter-occurrence interval count (default: 1)
OptionaluntilBounded end timestamp in epoch milliseconds, if bounded by UNTIL
Parsed structure of an RFC 5545 Recurrence Rule string.