code: func (c *Device) getAttribute(attr string) (string, error) {
  	resp, err := roundTripSingleResponse(c.server,
  		fmt.Sprintf("%s:%s", c.descriptor.getHostPrefix(), attr))
  	if err != nil {
  		return "", err
  	}
  	return string(resp), nil
  }
docs: // getAttribute returns the first message returned by the server by running
  // <host-prefix>:<attr>, where host-prefix is determined from the DeviceDescriptor.