@type t() :: %Gumroad.Subscriber{
  cancelled_at: nil,
  charge_occurrence_count: nil,
  created_at: String.t(),
  ended_at: nil,
  failed_at: nil,
  free_trial_ends_at: nil,
  id: String.t(),
  license_key: String.t(),
  product_id: String.t(),
  product_name: String.t(),
  purchase_ids: [String.t()],
  recurrence: String.t(),
  status: String.t(),
  user_email: String.t(),
  user_id: String.t(),
  user_requested_cancellation_at: nil
}