$ cat /etc/net/options.d/99-local 
WPA_SUPPLICANT=/sbin/wpasupplicant
IFPLUGSTATUS=/etc/net/scripts/ifplugstatus
me@hammer ~ $ cat /etc/net/scripts/ifplugstatus 
#!/bin/sh

rc=
for (( maxtry=5; $maxtry > 0; maxtry=$((maxtry-1)) )) ; do
    $DEFAULT_IFPLUGSTATUS "$@"
    rc=$?
    case "$rc" in
        2) break   ;; # beat detected
        3) sleep 1 ;; # no media, try again
    esac
done

exit $rc