This requires changing the underlying type, which *may* be a breaking change.AFAICT there isn't any way to do this with the struct based type, but canbe done with a slice type (or a map, but maps are heavier weight, so chose slice).When the slice is empty (len == 0) it is considered absent, when it has an itemit is considered present.This also allows for creating a value via:`Option[T]{value}`Any values appended to the slice after the first are ignored.