Is Queue.Queue.queue.clear() thread-safe?

[Russell Warren]

Thanks guys.  This has helped decipher a bit of the Queue mechanics for
me.

Regarding my initial clear method hopes... to be safe, I've
re-organized some things to make this a little easier for me.  I will
still need to clear out junk from the Queue, but I've switched it so
that least I can stop the accumulation of new data in the Queue while
I'm clearing it.  ie: I can just loop on .get until it is empty without
fear of a race, rather than needing a single atomic clear.

My next Queue fun is to maybe provide the ability to stuff things back
on the queue that were previously popped, although I'll probably try
and avoid this, too (maybe with a secondary "oops" buffer).

If curious why I want stuff like this, I've got a case where I'm
collecting data that is being asynchronously streamed in from a piece
of hardware.  Queue is nice because I can just have a collector thread
running and stuffing the Queue while other processing happens on a
different thread.  The incoming data *should* have start and stop
indications within the stream to define segments in the stream, but
stream/timing irregularities can sometimes either cause junk, or cause
you to want to rewind the extraction a bit (eg: in mid stream-assembly
you might realize that a stop condition was missed, but can deduce
where it should have been).  Fun.

Russ