code: func (h *Heartbeat) fetchAndAnnounce() error {
  	if err := h.fetch(); err != nil {
  		return trace.Wrap(err)
  	}
  	if err := h.announce(); err != nil {
  		return trace.Wrap(err)
  	}
  	return nil
  }
docs: // fetchAndAnnounce fetches data about server
  // and announces it to the server