Queue should have timeout option on get

[Kapil Thangavelu]

The distributed queue should be able to specify a timeout when fetching items from the queue. This should correctly errback on the get deferred, and should stop any in progress attempt to get a node from the queue node.

[Alex Parenteau (aubonbeurre)]

I agree somewhat, but I observed in our project that we would instead prefer to have a deferred that one can trigger to cancel the queue.get() (and therefore cancel the watcher).

This would require to use something like:

defer.DeferredList((watch_children, stop_get), fireOnOneCallback=True, fireOnOneErrback=True)

So one could stop the get call by issuing:

queue.stop_get.errback(Failure(QueueStopGet("Quit")))