[Users] ACK and re-INVITE ordering

[Jerome Martin]

Hi Bogdan,

> see in modules/dialog/dlg_hash.h the dlg_cell structure, state field. 
> There is no state yet saying if ACK was received or not, but I guess can 
> be added without problems

Going to take a look right now :-)

> the dialog module will export a new PV containing the dialog state.

OK, so no arbitrary pairs stored by config script. Don't you think that
would be usefull ? I could for instance implement my "pending ACK" using
this, without any added code in the module so to implement new state
information. Plus, the memory consumption of state info would be reduced
to only what the user actually needs (think of the acc module move from
1.1 to 1.2, making most fields optionnals via extra accounting).

Regards,
Jerome