How to Swetch Your Ils Tact?

In languages like haske, you can o cala, you can switch your io when you run your programme. You don't have to specify what kind of ao, sincne or sincronus is used. And i think the coride of sands io o that you can change your implementationyou cannot change o. Is it function? Is this function a sink or not? Its important as well. I made a joke to eat the other week about hin likeii'm sing to come back to the idea that threads are, you know, the way forward.