* `NS_AVAILABLE_IOS(10_0)` makes us tell our compiler that the method needs
  to be stamped into the TU but we promise to do stuff in it only on iOS 10.0
  and above.
* `@availability` ensures that if those methods are called on iOS versions less
  than 10.0, we will do nothing with it. This guards us against the case where
  iOS introduced the functionality privately in older versions of iOS.