public static bool AllAt <TSource, TPredicate>(this ImmutableHashSet <TSource> source, TPredicate predicate = default) where TPredicate : struct, IFunction <TSource, int, bool> => ValueReadOnlyCollectionExtensions.AllAt <ValueWrapper <TSource>, ImmutableHashSet <TSource> .Enumerator, TSource, TPredicate>(new ValueWrapper <TSource>(source), predicate);