Description of the custom MIME type "application/x-citadel-delivery-list"

 This MIME type may be found in the outbound queue room on Citadel systems,
which is typically called "__CitadelSMTPspoolout__".  The room is flagged as
a "system" room, which means that it's completely hidden to everyone, although
an Admin can get to it if the full name is specified (but unlike a normal
hidden room, it does not appear in the known rooms list on subsequent visits).
 
 Messages in this format contain delivery instructions.  Therefore, for each
message in the queue to be delivered to one or more recipients, there will be
*two* messages in the room: one containing the actual message, and the other
containing delivery instructions.  It is expected that the instructions
message may be replaced at any time (using an Exclusive ID field) if delivery
to only some of the recipients has been accomplished.
 
 Citadel keeps reference counts of each message on disk.  Therefore if a
message contains a mixture of local and remote recipients, there may be two
or more references to the message itself, one of them being the one in the
queue.
  
 A delivery list contains one or more lines of text, each line containing
a single instruction (usually a recipient).  Fields are separated by the
vertical bar character ("|") and there will always be at least one field on
each line.
 
 -- Once per Queue-Item --
 
 INSTRUCTION:  msgid
 SYNTAX:       msgid|0000000
 DESCRIPTION:  
    Defines the actual message for which we are providing delivery
    instructions.  This instruction must precede all the others.  When
    all deliveries have either succeeded or failed, both the instructions and
    the copy of the message itself in the queue room should be deleted.  The
    second parameter specifies the message ID in the local database.
 
 
 INSTRUCTION:  submitted
 SYNTAX:       submitted|999999999
 DESCRIPTION:
    Contains a timestamp designating when this message was first entered into
    the system.
 
 
 INSTRUCTION:  attempted
 SYNTAX:       attempted|999999999
 DESCRIPTION:
    Contains a timestamp designating the date/time of the last delivery
    attempt.
 
 
 INSTRUCTION:  retry
 SYNTAX:       retry|9999999
 DESCRIPTION:
    Citadel does not retry SMTP delivery at a fixed interval.  Instead, it
starts at a nominal interval (15 minutes by default) and then doubles the
interval after each failed attempt.  This instruction contains the interval
which should currently be followed (and doubled again, if the next delivery
fails).
  
  
 INSTRUCTION:  bounceto
 SYNTAX:       bounceto|Big Bad Sender[@host]
 DESCRIPTION:
    Where to send "bounce" messages (delivery status notifications).  The
    contents of the second field are supplied as the "recipient" field to
    CtdlSaveMsg(), and therefore may be a local username, a user on another
    Citadel, or an Internet e-mail address.
 

 INSTRUCTION:	envelope_from
 SYNTAX:	envelope_from|blurdybloop@example.com
 DESCRIPTION:
    Sets a value to be used as the envelope sender during the 'MAIL FROM:'
    phase of the SMTP transaction.  If an envelope sender is not supplied,
    one is extracted from the message body.

 INSTRUCTION:	source_room
 SYNTAX:	source_room|Citadel Support
 DESCRIPTION:
    when sending mailinglist rooms this contains the source room for displaying
    and messaging purposes.




-- Once per Remote-part per Queue-Item --

 INSTRUCTION:  remote
 SYNTAX:       remote|friko@mumjiboolean.com|0|delivery status message
 DESCRIPTION:
    Names a recipient on a remote system to which the message should be
    delivered.  The third parameter may contain any of the following values:
       0 = No delivery has yet been attempted
       2 = Delivery was successful
       3 = transient error state; like connection failure or DNS lookup failure
       4 = A transient error was experienced ... try again later
       5 = Delivery to this address failed permanently.  The error message
           should be placed in the fourth field so that a bounce message may
           be generated.