Day of the year this Date is on.
assert(YearMonthDay(1999, cast(Month) 1, 1).dayOfYear == 1); assert(YearMonthDay(1999, cast(Month) 12, 31).dayOfYear == 365); assert(YearMonthDay(2000, cast(Month) 12, 31).dayOfYear == 366);
See Implementation
Day of the year this Date is on.