code: func isShared(mount string, mountInfoPath string) (bool, error) {
  	info, err := findMountInfo(mount, mountInfoPath)
  	if err != nil {
  		return false, err
  	}
  
  	// parse optional parameters
  	for _, opt := range info.optionalFields {
  		if strings.HasPrefix(opt, "shared:") {
  			return true, nil
  		}
  	}
  	return false, nil
  }
docs: // isShared returns true, if given path is on a mount point that has shared
  // mount propagation.