A type-erased key path, from any root type to any resulting value type. NOTE: older runtimes had Swift.AnyKeyPath as the ObjC name. The two must coexist, so it was renamed. The old name must not be used in the new runtime. _TtCs11_AnyKeyPath is the mangled name for Swift._AnyKeyPath.
- Xcode 9.0+
- Swift Standard Library