There appear to be a number of things that must still be done to messages:
    .   Page nodes should have an entire page of data in addition to the
	overhead space required 
    .	We need allocators for these.  A single processor version is pretty
	easy (a free list per type)
    .


Events:
    .	When you create an event that might touch a session, you increment
	the reference count on the session.  The event handling function
	will decrement the reference count when it completes.  Should you
	cancel the event, if cancel returns true you decrement the reference
	count, since the handler will not run.  If cancel returns false, the
	handler will run and decrement the reference count.
