func ScanRunes(data []byte, atEOF bool) (advance int, token []byte, err error) {
	if atEOF && len(data) == 0 {
		return 0, nil, nil
	}

	// Fast path 1: ASCII.
	if data[0] < utf8.RuneSelf {
		return 1, data[0:1], nil
	}

	// Fast path 2: Correct UTF-8 decode without error.
	_, width := utf8.DecodeRune(data)
	if width > 1 {
		// It's a valid encoding. Width cannot be one for a correctly encoded

	}
	cfg.ListQuorum = listQuorum

	replicationPriority := env.Get(EnvAPIReplicationPriority, kvs.GetWithDefault(apiReplicationPriority, DefaultKVS))
	switch replicationPriority {
	case "slow", "fast", "auto":
	default:
		return cfg, fmt.Errorf("invalid value %v for replication_priority", replicationPriority)
	}
	cfg.ReplicationPriority = replicationPriority

const (
	// WorkerMaxLimit max number of workers per node for "fast" mode
	WorkerMaxLimit = 500

	// WorkerMinLimit min number of workers per node for "slow" mode
	WorkerMinLimit = 50

	// WorkerAutoDefault is default number of workers for "auto" mode
	WorkerAutoDefault = 100

	// MRFWorkerMaxLimit max number of mrf workers per node for "fast" mode
	MRFWorkerMaxLimit = 8

		n += wasSpace & ^isSpace
		wasSpace = isSpace
	}

	if setBits >= utf8.RuneSelf {
		// Some runes in the input slice are not ASCII.
		return FieldsFunc(s, unicode.IsSpace)
	}

	// ASCII fast path
	a := make([][]byte, n)
	na := 0
	fieldStart := 0
	i := 0
	// Skip spaces in the front of the input.
	for i < len(s) && asciiSpace[s[i]] != 0 {
		i++
	}
	fieldStart = i
	for i < len(s) {

	}
	last := &r.buf[len(r.buf)-1]
	return last.off + last.n
}

func (r *rleBuffer) Write(p []byte) (n int, err error) {
	var rp *repeatedByte
	if len(r.buf) > 0 {
		rp = &r.buf[len(r.buf)-1]
		// Fast path, if p is entirely the same byte repeated.
		if lastByte := rp.b; len(p) > 0 && p[0] == lastByte {
			if bytes.Count(p, []byte{lastByte}) == len(p) {
				rp.n += int64(len(p))
				return len(p), nil
			}
		}

			// Enable TCP open
			// https://lwn.net/Articles/508865/ - 32k queue size.
			_ = syscall.SetsockoptInt(fd, syscall.SOL_TCP, unix.TCP_FASTOPEN, 32*1024)

			// Enable TCP fast connect
			// TCPFastOpenConnect sets the underlying socket to use
			// the TCP fast open connect. This feature is supported
			// since Linux 4.11.
			_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, unix.TCP_FASTOPEN_CONNECT, 1)

	}

	// Help provides help for config values
	Help = config.HelpKVS{
		config.HelpKV{
			Key:         Speed,
			Description: `customize scanner speed (default|slowest|slow|fast|fastest)` + defaultHelpPostfix(Speed),
			Optional:    true,
			Type:        "string",
		},
		config.HelpKV{
			Key:         ExcessVersions,

				return cfg, err
			}
		}
	}

	switch speed := env.Get(EnvSpeed, kvs.GetWithDefault(Speed, DefaultKVS)); speed {
	case "fastest":
		cfg.Delay, cfg.MaxWait, cfg.Cycle = 0, 0, time.Second
	case "fast":
		cfg.Delay, cfg.MaxWait, cfg.Cycle = 1, 100*time.Millisecond, time.Minute
	case "default":
		cfg.Delay, cfg.MaxWait, cfg.Cycle = 2, time.Second, time.Minute
	case "slow":

	if err == io.EOF {
		err = io.ErrUnexpectedEOF
	}
	r.err = err
	return r.current, err
}

// next will read one entry from the stream.
// Generally not recommended for fast operation.
func (r *metacacheReader) next() (metaCacheEntry, error) {
	r.checkInit()
	if r.err != nil {
		return metaCacheEntry{}, r.err
	}
	var m metaCacheEntry
	var err error
	if r.current.name != "" {

		}
	}
	send := func(entry metaCacheEntry) error {
		objReturned(entry.metadata)
		select {
		case <-ctx.Done():
			return ctx.Err()
		case out <- entry:
		}
		return nil
	}

	// Fast exit track to check if we are listing an object with
	// a trailing slash, this will avoid to list the object content.
	if HasSuffix(opts.BaseDir, SlashSeparator) {
		metadata, err := s.readMetadata(ctx, pathJoin(volumeDir,