if err := lockedfile.Write(filepath.Join(c.dir, "trim.txt"), &b, 0666); err != nil {
		return err
	}

	return nil
}

// trimSubdir trims a single cache subdirectory.
func (c *DiskCache) trimSubdir(subdir string, cutoff time.Time) {
	// Read all directory entries from subdir before removing
	// any files, in case removing files invalidates the file offset
	// in the directory scan. Also, ignore error from f.Readdirnames,