code: func (client *Client) BeforeNotify(handler func(notice *Notice) error) {
  	client.beforeNotifyHandlers = append(client.beforeNotifyHandlers, handler)
  }
docs: // BeforeNotify adds a callback function which is run before a notice is
  // reported to Honeybadger. If any function returns an error the notification
  // will be skipped, otherwise it will be sent.