post-unlock — Notification of a successful path unlock.
The post-unlock hook runs after one
or more paths have been unlocked. It is typically used to
send email notification of the unlock event.
If the post-unlock hook returns a
nonzero exit status, the unlock will
not be aborted since it has already
completed. However, anything that the hook printed
to stderr will be marshalled back to the
client, making it easier to diagnose hook failures.