fmt::vformat_to_n

template<
    typename OutputIt,
    typename... T>
format_to_n_result<OutputIt>
vformat_to_n(
    OutputIt out,
    size_t n,
    string_view fmt,
    format_args args);

template<
    typename OutputIt,
    typename Char,
    typename... Args>
format_to_n_result<OutputIt>
vformat_to_n(
    OutputIt out,
    size_t n,
    basic_string_view<Char> fmt,
    basic_format_args<buffered_context<Char>> args);