code: public SubscriptionSchedule release() throws StripeException {
      return release((Map<String, Object>) null, (RequestOptions) null);
    }
docs: Releases the subscription schedule immediately, which will stop scheduling of its phases, but
  leave any existing subscription in place. A schedule can only be released if its status is
  <code>not_started</code> or <code>active</code>. If the subscription schedule is currently
  associated with a subscription, releasing it will remove its <code>subscription</code> property
  and set the subscription’s ID to the <code>released_subscription</code> property.