ctor for Buffer

Buffer.cs

internal Buffer(IEnumerable<TElement> source)
{
    TElement[] tElementArray = null;
    int count = 0;
    ICollection<TElement> tElements = source as ICollection<TElement>;
    if (tElements == null)
    {
        foreach (TElement tElement in source)
        {
            if (tElementArray != null)
            {
                if ((int)tElementArray.Length == count)
                {
                    TElement[] tElementArray1 = new TElement[count * 2];
                    Array.Copy(tElementArray, 0, tElementArray1, 0, count);
                    tElementArray = tElementArray1;
                }
            }
            else
            {
                tElementArray = new TElement[4];
            }
            tElementArray[count] = tElement;
            count++;
        }
    }
    else
    {
        count = tElements.Count;
        if (count > 0)
        {
            tElementArray = new TElement[count];
            tElements.CopyTo(tElementArray, 0);
        }
    }
    this.items = tElementArray;
    this.count = count;
}