[reSIProcate] How to answer a refer that was cancelled

[Robert Szokovacs <rszokovacs@xxxxxxxxxxxxxxx>]

Hi,

I have a resiprocate-based server accessed by a not-resiprocate-based client, 
sending a REFER. Sometimes I encounter the following situation: 
Since I do some async processing, it is possible that the client changes it's 
mind and cancels the REFER with expires=0.
And then I'm left with an unanswered request and I can't see a way around it, 
if I answer it from onExpiredByClient(), it will send the reply to the second 
REFER, the one with expires=0.
I suspect it's illegal for the client to send two messages in the same 
subscription without waiting for an answer, but the client does it anyway, so 
I need to handle it.
Any advise?

TIA

br

Szo