Method onStopped

tests/test_ws.cpp:99–99

protected:
    void onStarted() override { started = true; }
    void onStopped() override { stopped = true; }
    void onConnected(std::shared_ptr<TCPSession>& session) override { connected = true; ++clients; }
    void onDisconnected(std::shared_ptr<TCPSession>& session) override { disconnected = true; --clients; }
    void onError(int error, const std::string& category, const std::string& message) override { errors = true; }