code: func (e *Ethtool) Change(intf string, config map[string]bool) error {
  	names, err := e.FeatureNames(intf)
  	if err != nil {
  		return err
  	}
  
  	length := uint32(len(names))
  
  	features := ethtoolSfeatures{
  		cmd:  ETHTOOL_SFEATURES,
  		size: (length + 32 - 1) / 32,
  	}
  
  	for key, value := range config {
  		if index, ok := names[key]; ok {
  			setFeatureBit(&features.blocks, index, value)
  		} else {
  			return fmt.Errorf("unsupported feature %q", key)
  		}
  	}
  
  	return e.ioctl(intf, uintptr(unsafe.Pointer(&features)))
  }
docs: // Change requests a change in the given device's features.