func readDir(dirPath string) (entries []string, err error) {
	return readDirWithOpts(dirPath, readDirOpts{count: -1})
}

// Return up to count entries at the directory dirPath.
func readDirN(dirPath string, count int) (entries []string, err error) {
	return readDirWithOpts(dirPath, readDirOpts{count: count})