code: func (c *Client) Set(key, value string) error {
  	key = strings.ToUpper(key)
  	if value != "" {
  		value = " " + value
  	}
  	val := "SET" + key + value + "\n"
  	if _, err := c.in.Write([]byte(val)); err != nil {
  		return err
  	}
  	line, _, _ := c.out.ReadLine()
  	if string(line) != "OK" {
  		return errors.Errorf("error: %s", line)
  	}
  	return nil
  }
docs: // Set sets a key