public void ReadOnlyObservableCollection_ObserveRemoveChangedItemsTest()
        {
            var l = new List <string[]>();
            var c = new ObservableCollection <string>(new[] { "a", "b", "c" });
            var r = new ReadOnlyObservableCollection <string>(c);

            r.ObserveRemoveChangedItems()
            .Subscribe(x => l.Add(x));

            l.Count.Is(0);

            c.Remove("a");
            l[0].Is("a");

            c.RemoveAt(1);
            l[0].Is("a");
            l[1].Is("c");
        }