public static ReadOnlyListExtensions.WhereAtEnumerable <ValueWrapper <TSource>, TSource, TPredicate> WhereAt <TSource, TPredicate>(
this ImmutableList <TSource> source,
TPredicate predicate = default)
where TPredicate : struct, IFunction <TSource, int, bool>
=> ReadOnlyListExtensions.WhereAt <ValueWrapper <TSource>, TSource, TPredicate>(new ValueWrapper <TSource>(source), predicate);