How would I change the syslog event message on an output module so that every message gets an additional field?  I want to add another value called "Project X" after the message portion of all syslogs events/messages as they are forwarded to another server?  Would I use $raw_event as I show in my example? 

Current config:

<Output out>

   Module om_udp

   Host 192.168.1.10

   Port 514

</Output>

Would I do this?

<Output out>

   Module om_udp

   Host 192.168.1.10

   Port 514

   Exec $raw_event = $raw_event + "Project X";

</Output>

OR is it more like this...?

<Output Out>

   Module om_udp

   Host 192.168.1.10

   Port 514

   $Message = $Message + "Project X"

   Exec to_syslog_bsd();

</Output out>