>>>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