Method operator()

include/boost/asio/impl/append.hpp:48–53

  template <typename... Args>
  void operator()(Args&&... args)
  {
    this->invoke(
        index_sequence_for<Values...>{},
        static_cast<Args&&>(args)...);
  }

  template <std::size_t... I, typename... Args>
  void invoke(index_sequence<I...>, Args&&... args)