code: func (n *hostOnlyNetwork) SaveIPv4(vbox VBoxManager) error {
  	if n.IPv4.IP != nil && n.IPv4.Mask != nil {
  		if runtime.GOOS == "windows" {
  			log.Warn("Windows might ask for the permission to configure a network adapter. Sometimes, such confirmation window is minimized in the taskbar.")
  		}
  
  		if err := vbox.vbm("hostonlyif", "ipconfig", n.Name, "--ip", n.IPv4.IP.String(), "--netmask", net.IP(n.IPv4.Mask).String()); err != nil {
  			return err
  		}
  	}
  
  	return nil
  }
docs: // SaveIPv4 changes the ipv4 configuration of the host-only network.