private static void CommpareAdd(ObservableCollection<Item> collection, ObservableCompositeCollection<Item> compositeCollection)
{
var data = CreateData();
var stopwatch = Stopwatch.StartNew();
var t1 = stopwatch.Elapsed;
collection.AddRange(data.SelectMany(list => list));
var t2 = stopwatch.Elapsed;
compositeCollection.Content.AddRange(data);
var t3 = stopwatch.Elapsed;
stopwatch.Stop();
var compositeTime = t3 - t2;
var plainTime = t2 - t1;
var factor = compositeTime.TotalSeconds / plainTime.TotalSeconds;
Debug.WriteLine("composite: {0} / plain {1} = {2}", compositeTime, plainTime, factor);
Debug.WriteLine("{0} elements.", compositeCollection.Count);
Assert.IsTrue(factor < 2);
Assert.IsTrue(collection.SequenceEqual(compositeCollection));
}
