Capturing persistent connections to logfile

I am using the following rule in one environment:

rule reject_when_down {
   when CLIENT_ACCEPTED {
   if { [active_members pool] == 0 } {
      discard
      } else {
             use pool pool
           if { not (([IP::client_addr] eq "ip1") || ([IP::client_addr] eq "ip2")) } {
              persist source_addr 28800
           }
      }
}
}

Is there a way to log when the persistent entry is used in lieu of a new load balancing decision?