Cope with possibility of duplicate uuid, in e.g. queue/fanout/direct.
If a subscription token matches an existing subscription, there's a
collision, so choose a new token until there's no collision.

SAX-style sexp reader/writer, so that we can do something sensible for
enormous (e.g. gigabyte-sized) messages.

The "meta" exchange probably wants to be a topic exchange. Or
something.

The "meta" exchange probably wants to emit how-things-are-now messages
when people subscribe to it, to get them started; a kind of
last-value-cache type thing.

Website
 - http://www.flickr.com/photos/elemishra/158211069/

Switch from indirect scheduling to direct scheduling
 - before, on walk: 173kHz test1/test3
 - after, no change. Probably because we only have a single thread
   active in the system when running test1/test3, so every time some
   work comes in, it baton-passes to the next guy in the chain. The
   change *would* be an improvement but we have a separate worklist
   (to process now) and runlist (to process after polling for events
   once) so it always goes back to the scheduler because the worklist
   is never longer than one.
 - Revisit once we start testing multiple concurrent streams.