lockfile.go
func New(path string) (Lockfile, error) {
	if !filepath.IsAbs(path) {
		return Lockfile(""), ErrNeedAbsPath
	}
	return Lockfile(path), nil
}
func New(path string) (Lockfile, error) {
	if !filepath.IsAbs(path) {
		return Lockfile(""), ErrNeedAbsPath
	}
	return Lockfile(path), nil
}
// New describes a new filename located at the given absolute path.