title: Passing Core Data FetchedResults<T> for previews in SwiftUI
body: <p>I have a parent view which does a <code>@FetchRequest</code> and passes the <code>FetchedResults&lt;T&gt;</code> to a child view. Everything works, and the child view is able to parse through the <code>FetchedResults</code>. However, I can't figure out how to set up the data so that the child's <code>Preview</code> struct will work. What's the proper way to set up some constant data in <code>Preview</code> struct so that I can instantiate the child view and pass in <code>FetchedResults&lt;T&gt;</code>?</p>