Allow useTask to be used outside of setup

This could be useful for testing.

It seems the only blocker for this is the usage of onUnmounted() which would cause an error if used outside of setup. It could be conditionally turned off so that useTask() can be used anywhere.

 const mockTask = useTask(function*() {
      return "success";
    }, { cancelOnUnmount: false });
  const wrapper = mount(SaveButton, {
    propsData: {
      task,
    },
  });

  task.perform();
  expect(wrapper.find("button")).toBeDisabled();
 });

[MartinMalinda]

@dschmidt Thanks for the reminder. I’ll try to check the testing workflows with cancelOnUnmount: false and update that docs page and then close this issue 👍

https://vue-concurrency.netlify.app/testing/

[MartinMalinda]

@rudolfbyker no, it still stands on top of composition api. It’s just that just like ref and computed can be used outside of the setup function, so can tasks now