Method onConnection

examples/protobuf/codec/server.cc:44–49

 private:
  void onConnection(const TcpConnectionPtr& conn)
  {
    LOG_INFO << conn->peerAddress().toIpPort() << " -> "
        << conn->localAddress().toIpPort() << " is "
        << (conn->connected() ? "UP" : "DOWN");
  }

  void onUnknownMessage(const TcpConnectionPtr& conn,
                        const MessagePtr& message,