I'm trying to understand how ARCMail mailers work so I can implement
ARCMail support in a current BSO only supported tosser.

What I need to understand is how is the tosser going to recognize
that a particular *.MSG is in the process of being sent to the
destination address?  Is there any type of "locking" or "busy" 
file that FrontDoor implements so that the tosser knows not to 
bundle a new packet in a bundle that may be in the process of 
being sent?

Or does FrontDoor open the bundle in exclusive mode so the tosser 
fails when it tries to add the packet and knows to create a new 
bundle at this point?  

Or does the tosser always suppose to create a new bundle regardless 
and never try to append packets to an existing bundle in ARCMail 
systems unlike BSO?

If anyone can point me in the direction of some technical documentation
or provide me feedback to my questions, I'd be grateful.

Thanks,
Chris
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