public void AddRange(RazorDiagnosticCollection items)
        {
            if (items == null)
            {
                throw new ArgumentNullException(nameof(items));
            }

            _inner.AddRange(items);
        }
            public Enumerator(RazorDiagnosticCollection collection)
            {
                if (collection == null)
                {
                    throw new ArgumentNullException(nameof(collection));
                }

                _items = collection._inner;
                _index = -1;
            }