Eventmachine talk - Apr 2008 - EM outbound message pacing: howto?

Hi Group,
I''d like to be able to set a pacing behavior on outbound messages, in
this case one call of send_data is a message.
Two scenarios come to mind.
 a) send_data with some fixed time interval between calls, send_data
data is queued if more calls are made than can be
''allowed''/processed
 b) send_data freely until some max_count during an interval is
reached, then queue messages until the end of the interval and resume
sending the queued messages.

 - From what I''ve seen neither of these behavior are configurable
(already implemented) in EM - correct?

Could anyone indicate what methods I might look at to implement these,
that will at least give me a starting point to work from.
Is there an existing project/example that implements a) or b) which I
should look at?

Cheers
Mark