public static TSource?SingleOrNull <TEnumerator, TSource>(this CreateValueEnumerable <TEnumerator, TSource> source)
where TEnumerator : struct, IValueEnumerator <TSource>
where TSource : struct
=> ValueEnumerable.SingleOrNull <CreateValueEnumerable <TEnumerator, TSource>, TEnumerator, TSource>(source);
public static TSource?FirstOrNull <TEnumerator, TSource>(this CreateValueEnumerable <TEnumerator, TSource> source, Func <TSource, bool> predicate)
where TEnumerator : struct, IValueEnumerator <TSource>
where TSource : struct
=> ValueEnumerable.FirstOrNull <CreateValueEnumerable <TEnumerator, TSource>, TEnumerator, TSource>(source, predicate);
