/// <summary> /// Returns a sequence of asynchronously selected values, zero or more for each element in the source sequence. /// </summary> public static IAsyncEnumerator <TCollection> SelectMany <TSource, TCollection>( this IAsyncEnumerator <TSource> source, Func <TSource, Task <IEnumerable <TCollection> > > collectionSelector) { return(source.SelectMany(collectionSelector, (s, c) => c)); }