code: func (client *Client) QueryMetrics(from, to int64, query string) ([]Series, error) {
  	v := url.Values{}
  	v.Add("from", strconv.FormatInt(from, 10))
  	v.Add("to", strconv.FormatInt(to, 10))
  	v.Add("query", query)
  
  	var out reqMetrics
  	err := client.doJsonRequest("GET", "/v1/query?"+v.Encode(), nil, &out)
  	if err != nil {
  		return nil, err
  	}
  	return out.Series, nil
  }
docs: // QueryMetrics takes as input from, to (seconds from Unix Epoch) and query string and then requests
  // timeseries data for that time peried