code: func (nc *Conn) SetDiscoveredServersHandler(dscb ConnHandler) {
  	if nc == nil {
  		return
  	}
  	nc.mu.Lock()
  	defer nc.mu.Unlock()
  	nc.Opts.DiscoveredServersCB = dscb
  }
docs: // SetDiscoveredServersHandler will set the discovered servers handler.