I was reading chapter 3 of the official docs, but I'm still in doubt if
queue runners reroute the address(es) of a message in the queue, and
then re-transport it.
Or if it just re-transport the message with the data originally set in
route time.
For example, lets say that when a message is received, a manualroute
router looks up 'route_data' in mysql, and the result is 1.2.3.4.
But the message could not be delivered, and 2 hours later when the queue
runner processes that message, there is a new value for 'route_data' in
mysql (4.3.2.1).
Which value of 'route_data' will be used when retrying? 1.2.3.4 or 4.3.2.1?
