renamed Field.Computed to Field.Virtual to distinguish from Field.Derived

Sources/DynamicObject.swift

@@ -114,7 +114,8 @@ extension NSManagedObject: DynamicObject {
     
     public class func cs_fromRaw(object: NSManagedObject) -> Self {
         
-        return unsafeDowncast(object, to: self)
+        // unsafeDowncast fails debug assertion starting Swift 5.2
+        return _unsafeUncheckedDowncast(object, to: self)
     }
     
     public static func cs_matches(object: NSManagedObject) -> Bool {