Re: Exchange type issue

I appreciate all the comments made and understand the proposal (and have 
discussed with Charlton). I agree with Charlton, Abbie and Martin.

One important point, a notification can be a request or a response, 
given how you look at it (which indicated to Charlton). I think the flag 
is appropriate because the notification could be an identifier on either 
(and as such we may consider that). Semantically the notify is no 
different than either (as I said given how you look at it - as a one-way 
request or a request-respond). Thanks.