A rather randomly ordered set of notes.

- Implement poll/peek on read end. (It's impossible to identify complete
  messages in advance, but within the framework only complete messages
  are sent.)
- Can gevent's FileObjectPosix be of any use?
- hub.cancel_wait() (cf. gevent sockets) in close instead of lock check?
- put() timeout? Relevant in case of pipe being full. However, put()
  duration cannot be controlled if write is blocking *after* partial
  msg write. Doesn't make sense I think.
- Implementation on Windows based on NamedPipes with overlapping IO
  would provide more control oder larger performance. libuv backend instead
  of libev would be helpful. gevent needs to make this progress, gipc would
  take advantage.
