message: Add copy special members
diff: @@ -41,6 +41,9 @@ private:
  boost::optional<boost::asio::io_service::work> work_;
  public:
  + async_echo_server(async_echo_server const&) = delete;
  + async_echo_server& operator=(async_echo_server const&) = delete;
  +
  async_echo_server(std::ostream* log,
  std::size_t threads)
  : log_(log)
  