---Broad outline:
Get packets
Tally stats
Mangle them
Tally stats
Send 'em out


B---road outline, 10x magnification:
Get packets from packet engine
Run them through the tally object
Mangle packets with custom packet mangler (TM)
Tally object...
Send them out through the packet engine

---Broad outline, 100x mag:
foreach $packet_engine ( @all_packet_engines ) {
 push @incoming_packet_queue, $packet_engine_object->get_packets;
}

$stats_object->tally(@incoming_packet_queue);

@outgoing_packet_queue = $function_object->mangle(@incoming_packet_queue);
@incoming_packet_queue = ();

$stats_object->tally(@outgoing_packet_queue);

foreach $packet ( @outgoing_packet_queue ) {
 #insert clever routing logic for packets e.g.
 foreach $engine ( @all_packet_engines ) {
 if ( $packet->{ATTRIB} == $engine->{ATTRIB} ) {$engine->send($packet)}
 }
}