public void Insert(int index, GradientStop stop)
    {
      if (stop == null)
      {
        throw new ArgumentNullException("stop");
      }

      List.Insert(index, stop);
    }
    public int IndexOf(GradientStop stop)
    {
      if (stop == null)
      {
        throw new ArgumentNullException("stop");
      }

      return List.IndexOf(stop);
    }
    public void CopyTo(GradientStop[] array, int arrayIndex)
    {
      if (array == null)
      {
        throw new ArgumentNullException("array");
      }

      List.CopyTo(array, arrayIndex);
    }
    public bool Contains(GradientStop stop)
    {
      if (stop == null)
      {
        throw new ArgumentNullException("stop");
      }

      return List.Contains(stop);
    }
    public void Add(GradientStop stop)
    {
      if (stop == null)
      {
        throw new ArgumentNullException("stop");
      }

      List.Add(stop);
    }
    public bool Remove(GradientStop stop)
    {
      if (stop == null)
      {
        throw new ArgumentNullException("stop");
      }

      if (List.Contains(stop) == false)
      {
        return false;
      }

      List.Remove(stop);

      return true;
    }