Log deliver by MTA option

Transaction logging MTA options:  (0-3)
(New in MS 8.0.1.) The  MTA option controls whether or not any SMTP DELIVERBY value (see RFC 2852) is included in MTA message transaction log entries and/or    mapping table probes. Setting bit 0 (value 1) causes the DELIVERBY time value, expressed as an offset in seconds from the current time, a semicolon, the DELIVERBY mode, and (if trace information is present) the trace value, to be logged immediately after the priority is logged, before the  alternate recipient. A " " attribute is used in the XML log format. If bit 1 (value 2) is set in the  MTA option,  then this information appears in the    mapping table probe immediately after the  priority, before the  alternate recipient.

See also:
 * deliverbymin Option
 * deliverbychannel Option
 * log_priority MTA Option
 * log_alternate_recipient MTA Option
 * Transaction logging MTA options
 * MTA transaction logging
 * Triggering effects from transaction logging with LOG_ACTION
 * log_format MTA Option