private static void UsingObservableImpl()
{
var a = new ObservableImpl<string>();
a.Where(item => item is ObservableImpl<string>.ItemAdded)
.Subscribe(item => Console.WriteLine("Added: " + item));
a.Where(item => item is ObservableImpl<string>.ItemRemoved)
.Subscribe(item => Console.WriteLine("Removed: " + item));
a.Add("a");
a.Add("b");
a.Add("c");
a.Add("d");
a.Add("e");
a.Add("f");
}
