Protocol metatype extensions (to better support SwiftUI)

[anandabits (Matthew Johnson)]

@MutatingFunk

General question on the existing StaticMember: Is this type special-cased in the language (despite being in SwiftUI), or this a workaround anyone can use (as this thread suggests)?

This is a technique anyone can use. I posted some code showing how to do this in the previous thread on this topic.