GenericAmplitudePropertySetterFactory
class GenericAmplitudePropertySetterFactory(amplitude: Amplitude) : AmplitudePropertySetterFactory, FallbackFactory(source)
Sets any property as an Amplitude user property. Claims everything, so it belongs last in a chain.
Amplitude has a single store for attributes — the user's — so a UserProperty and a plain Property go to the same place and this one factory covers both.