OnUnitIdle override not working

I am following the tutorial [here ](https://github.com/Blizzard/s2client-api/blob/master/docs/tutorial2.md) but when I try to print a simple string after overriding OnUnitIdle nothing happens.

This is what I use:
`virtual void OnUnitIdle(const Unit* unit) final { std::cout << "TEST" << std::endl......`.
Then I create a worker and let it do nothing, but there is no message in the console window.