boost::gil::any_image_view::emplace

template<
    std::size_t I,
    class V,
    class... A>
requires std::is_constructible<mp11::mp_at_c<variant<T...>, I>, std::initializer_list<V>&, A&&...>::value
constexpr
variant_alternative_t<I, variant<T...>>&
emplace(
    std::initializer_list<V> il,
    A&&... a);