Best way to serialize a date without a year [Answered]

I want to serialize a date, ideally in such a way that it could be deserialized into a

DateOnly

DateOnly

. I don't really need the year, and I would also like to be able to include February 29, so I can't just serialize it as

"02-29"

"02-29"

or something as that is year 0001. Is there any good way of serializing a specific date like this?