there is three method to send a task message to broker:
apply_async(args, kwargs[, …])
delay is clearly convenient, but if you want to set additional
execution options you have to use apply_async.
Tips if the task is not registered in the current process, you can use send_task() to call the task by name instead.
Linking(callbacks/errbacks) aka. Chain
in practice the link execution options is considered an internal primitive, and you will probably not use it directly, but use chains instead.