Reference to non-static member function must be called on templated class

I have a class used to wrap boost::asio and I use templates to define delegates:

template <class T>
  struct Socket : public std::enable_shared_from_this<Socket<T>> {

    explicit Socket<T>(T &delegate, const std::string &socket) : endpoint_{socket} {
      socket_.reset(new asio::generic::stream_protocol::socket(service_));
      socket_->connect(endpoint_, delegate_.error_code);
      socket_->non_blocking(true);
    }

    void read() const noexcept {
      std::vector<byte> bytes;
      asio::async_read(*socket_, asio::buffer(bytes), asio::transfer_all(), delegate_.on_read);
    }

    virtual ~Socket<T>() noexcept = default;

   private:
    asio::io_service service_;
    std::unique_ptr<asio::generic::stream_protocol::socket> socket_;
    asio::local::stream_protocol::endpoint endpoint_;
    T delegate_;
    std::vector<byte> buffer_;
  };

My problem is that passing the delegate method as a handler to asio::async_read results in the error

Reference to non-static member function must be called

What's the correct syntax to do this?