Is there a built-in way to convert IEnumerator to IEnumerable

static class Helper
{
  public static List<T> SaveRest<T>(this IEnumerator<T> enumerator)
  {
    var list = new List<T>();
    while (enumerator.MoveNext())
    {
      list.Add(enumerator.Current);
    }
    return list;
  }
  public static ArrayList SaveRest(this IEnumerator enumerator)
  {
    var list = new ArrayList();
    while (enumerator.MoveNext())
    {
      list.Add(enumerator.Current);
    }
    return list;
  }
}