code: func (rc *RequestConfig) SetQuery(query H) *RequestConfig {
  	f := make(url.Values)
  
  	for k, v := range query {
  		f.Set(k, v)
  	}
  
  	if strings.Contains(rc.Path, "?") {
  		rc.Path = rc.Path + "&" + f.Encode()
  	} else {
  		rc.Path = rc.Path + "?" + f.Encode()
  	}
  
  	return rc
  }
docs: // SetQuery supply query string.