Function connect_shared

test/exec/asio/test_completion_token.cpp:134–139

  template <typename Sender, typename Receiver>
  auto connect_shared(Sender&& sender, Receiver&& receiver)
  {
    return std::make_shared<connect_shared_operation_state<Sender, Receiver>>(
      std::forward<Sender>(sender),
      std::forward<Receiver>(receiver));
  }

  template <typename Sender, typename Receiver>
  void