How to cancel io_service object in a thread?

My understanding is that to end this timer thread, I need to call stop() on the io_service object. I'm doing this so that the MyClass object (also running as a thread) doesn't end in an active exception when it's thread ends.

How does one cancel an io_service object in a standard thread using a lambda?

class MyClass
{
    private:
        boost::asio::io_service io;

    // ...
}

void MyClass::operator()()
{
    boost::asio::deadline_timer my_timer(io,
        boost::posix_time::seconds(300));

    my_timer.async_wait(boost::bind(&MyTest::pump, this,
        boost::asio::placeholders::error, &my_timer));

    std::unique_ptr<std::thread> io_thread(
        std::make_unique<std::thread>([&] { io.run(); }));


    // ...

    // cancel here.

}