code: func (m *wsNotificationManager) RegisterSpentRequests(wsc *wsClient, ops []*wire.OutPoint) {
  	m.queueNotification <- &notificationRegisterSpent{
  		wsc: wsc,
  		ops: ops,
  	}
  }
docs: // RegisterSpentRequests requests a notification when each of the passed
  // outpoints is confirmed spent (contained in a block connected to the main
  // chain) for the passed websocket client.  The request is automatically
  // removed once the notification has been sent.