>>>>Adding an extension method ( say AddCollection) is a bad idea since it accepts an argument of IEnumerable(T).
>>>>
>>>>using items.Count() is slow - I guess it uses a foreach loop to count
>>>>
>>>>

>>>>// don't do this at home
>>>>
>>>>public static void AddCollection<T>(this List<T> list, IEnumerable<T> items)
>>>>		{
>>>>
>>>>			if (items.Count() <= Tuning.AddRangeMinimumItems) // 128
>>>>			{
>>>>				foreach (T item in items)
>>>>					list.Add(item);
>>>>			}
>>>>			else
>>>>			{
>>>>				list.AddRange(items);
>>>>			}
>>>>		}
>>>>

>>>>
>>>>An extension method that takes a whole array is a better idea - since array.Length is faster
>>>
>>>And probably I wouldn't use such an extesnion when it already exists (Concat):
>>>

>>>       static void UseConcat()
>>>        {
>>>            int[] buf = new int[Size];
>>>            List<int> list = new List<int>();
>>>            for (int i = nTimes; --i != 0; )
>>>            {
>>>                list.Concat(buf);
>>>                list.Clear();
>>>            }
>>>       }
>>>

>>>Cetin
>>
>>
>>I thought so as well - for a couple of minutes
>>
>>They are both extension methods - but they are not doing the same, ie one works on the list whereas the other returns another Enumerator
>
>Yes and I can't see why I wouldn't want that. That is exactly what I would like it to be (but that is me:).
>Cetin

Not sure what you mean here, Cetin