could be very unimportant (i.e., it should let the others go first).
MailMan usually sends out the messages in the queue according to their date
of creation. However, the POSTMASTER may use the 'toggle transmit priority'
command (i.e., 'X'), to change the transmit priority. Thus, some messages
can be flagged to transmit before the rest (high priority), while others can
be flagged to transmit after the rest (low priority).
Messages waiting to be sent to remote domains are placed in special baskets
owned by the POSTMASTER. We call these the transmit queues. The POSTMASTER
is able to manipulate, to a certain degree, the order in which they are sent.
Sometimes, messages stack up in the transmit queues waiting to be delivered.
One or more of these messages could be very important (i.e., it needs to go
first). For example, one of the messages could be a site's payroll data
destined for FOC-AUSTIN.DOMAIN.EXT. Conversely, one or more of these messages