SubscriptionStatus

The lifecycle status of a subscription: * `PendingAuthorization` - created, awaiting customer authorisation via `redirectUrl`. * `Active` - authorised; scheduled charges are being taken. * `Canceled` - cancelled; no further charges. * `Completed` - all scheduled occurrences have been taken. * `Expired` - the authorisation lapsed before activation. * `Failed` - the subscription could not be established or sustained. * `Unknown` - the status could not be determined.