code: func (mp *MachinePool) SwarmingURL() string {
  	if mp.SwarmingHost == "" {
  		return ""
  	}
  	u := &url.URL{
  		Scheme: "https",
  		Host:   mp.SwarmingHost,
  		Path:   "botlist",
  		RawQuery: url.Values{
  			"f": mp.Dimensions,
  		}.Encode(),
  	}
  	return u.String()
  }
docs: // SwarmingURL returns the swarming bot URL for the machine pool, if available.