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);