public void CleanupTask()
{
IPortReceive pa = new Port <int> ();
IPortReceive pb = new Port <string> ();
ITask task = new Task<int, string> ((i, s) => { });
var mr = new MultipleItemReceiver (task, pa, pb);
var dq = new SerialDispatchQueue ();
mr.TaskQueue = dq;
mr.Execute ();
((Port<int>)pa).Post (10);
Assert.AreEqual (0, pa.ItemCount, "#1");
mr.Cleanup (task);
Assert.AreEqual (1, pa.ItemCount, "#2");
Assert.AreEqual (0, pb.ItemCount, "#3");
}