Read the section called "Asynchronous Operations". Basically, anything except a GET could take longer than the client calling the API planned on. That is currently the only way tasks start. So it could be an action (POST), it could be a Create (POST), delete (DELETE) or even modify (PUT/PATCH) at least theoretically. We have it on our list to create a YouTube video on Tasks, but it may be a few more weeks at least.