add comparator

example/lib/main.dart

@@ -44,6 +44,7 @@ class _MyAppState extends State<MyApp> {
                 favorite: ['+39', 'FR'],
                 showFlag: false,
                 showFlagDialog: true,
+                comparator: (a, b) => b.name.compareTo(a.name),
                 //Get the country information relevant to the initial selection
                 onInit: (code) => print("${code.name} ${code.dialCode}"),
               ),