/// <summary>
/// Concatenate with the error signal.
/// </summary>
/// <param name="source">The source to append an error to</param>
/// <param name="error">Th error to append</param>
/// <typeparam name="TSource">The element type of the sequence</typeparam>
/// <returns>The new IAsyncEnumerable instance.</returns>
internal static IAsyncEnumerable <TSource> WithError <TSource>(this IAsyncEnumerable <TSource> source, Exception error)
{
return(source.ConcatWith(AsyncEnumerable.Error <TSource>(error)));
}
