code: func GetTotalUsedFds() int {
  	if fds, err := ioutil.ReadDir(fmt.Sprintf("/proc/%d/fd", os.Getpid())); err != nil {
  		logrus.Errorf("Error opening /proc/%d/fd: %s", os.Getpid(), err)
  	} else {
  		return len(fds)
  	}
  	return -1
  }
docs: // GetTotalUsedFds Returns the number of used File Descriptors by
  // reading it via /proc filesystem.