public void AddRange_AddSelfAsEnumerable_ThrowsExceptionWhenNotEmpty()
        {
            PooledList <T> list = GenericListFactory(0);

            // Succeeds when list is empty.
            list.AddRange(list);
            list.AddRange(list.Where(_ => true));

            // Succeeds when list has elements and is added as collection.
            list.Add(default);