code: func (vm *VirtualMachine) logPrintf(format string, v ...interface{}) {
  	f, err := os.OpenFile(vm.log, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0)
  	if err != nil {
  		log.Println(err)
  		return
  	}
  	log.New(f, "vmx ", log.Flags()).Printf(format, v...)
  	_ = f.Close()
  }
docs: // Rather than keep an fd open for each VM, open/close the log for each messages.
  // This is ok for now as we do not do any heavy VM logging.