[Flow] JobQueue Questions

[Carsten Bleicker]

Maybe somebody could explain some questions about the JobQueue Package?
1. What is exactly a "Payload"
2. How to use Message and Queue in an implementation of a JobInterface?
public function execute(QueueInterface $queue, Message $message);
I saw this example of bastian.
https://gist.github.com/bwaidelich/7529881

But there is no usage of message and queue.
Whate are they for? 

Thanks a lot
Carsten