This hook will be called when the subscriber's quota is initialised to the value defined in the SPR data plan. The quota is initialised typically when during the first use or subsequently when the remaining quota is initialised by provisioning system or for some other external reason.

The default hook will log the event, but you may change the hook to call send SMS, call an external process or do any other action.

The following arguments are passed to the hook in the following order: