public IDbAsyncEnumerator <TElement> ExecuteQueryAsync <TElement>( Expression expression) { var query = asyncProvider.CreateQuery <TElement>(expression) as IDbAsyncEnumerable <TElement>; if (query == null) { throw new InvalidOperationException( "Decorated query provider of AuthorizingQueryProvider doesn't support async queries: " + provider.ToString()); } return(query.GetAsyncEnumerator()); }