#include <mutex>

struct connection_info {
};

struct data_packet {
};

struct connection_handle {
  void send_data(data_packet const&) {}
  data_packet receive_data() { return data_packet(); }
};

struct remote_connection_manager {
  connection_handle open(connection_info const&) { return connection_handle(); }
} connection_manager;

class X {
private:
  connection_info connection_details;
  connection_handle connection;
  std::once_flag connection_init_flag;

  void open_connection()
  {
    connection = connection_manager.open(connection_details);
  }

public:
  X(connection_info const& connection_details_)
      : connection_details(connection_details_)
  {
  }
  void send_data(data_packet const& data)
  {
    std::call_once(connection_init_flag, &X::open_connection, this);
    connection.send_data(data);
  }
  data_packet receive_data()
  {
    std::call_once(connection_init_flag, &X::open_connection, this);
    return connection.receive_data();
  }
};

int
main()
{
}