After deliberating on the APIs for properties that can have a single
type vs multiple types, I've decided to keep the distinctly separate
APIs for the single-type properties. This means humans reading the APIs
will use simpler and more reasonable getters/setters, etc. However, by
default the two kinds of properties will not be able to satisfy the same
interface.
If this is needed, in the future we can auto-generate thin-wrapper types
around single-type properties that cause them to have a shared API with
the multi-type properties. But that won't be tackled for now, as its
expected use case is small.
Cory Slep