title: Alternative to using a Singleton or AppDelegate for global data storage
body: <p>I have an app that needs access to a set of user data that can't be stored on disk. My typical approach in the past would be to create a singleton to hold this data with a concurrent queue for each property to make data reads/writes thread safe. </p>
  
  <p>What I am wondering is if there is a way to do this without the use of Singletons or storing a reference to my user data in my AppDelegate. </p>