ListObjectVersions(ctx context.Context, bucket, prefix, marker, versionMarker, delimiter string, maxKeys int) (result ListObjectVersionsInfo, err error)
	// Walk lists all objects including versions, delete markers.
	Walk(ctx context.Context, bucket, prefix string, results chan<- ObjectInfo, opts WalkOptions) error

	// Object operations.

	// GetObjectNInfo returns a GetObjectReader that satisfies the

	ListVols(ctx context.Context) (vols []VolInfo, err error)
	StatVol(ctx context.Context, volume string) (vol VolInfo, err error)
	DeleteVol(ctx context.Context, volume string, forceDelete bool) (err error)

	// WalkDir will walk a directory on disk and return a metacache stream on wr.
	WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) error

	// Metadata operations

	if err != nil {
		return err
	}

	wk, err := workers.New(workerSize)
	if err != nil {
		// invalid worker size.
		return err
	}

	walkQuorum := env.Get("_MINIO_BATCH_REPLICATION_WALK_QUORUM", "strict")
	if walkQuorum == "" {
		walkQuorum = "strict"
	}

	retryAttempts := ri.RetryAttempts
	retry := false
	for attempts := 1; attempts <= retryAttempts; attempts++ {

		sort.Strings(closestCommands)
		// Suggest other close commands - allow missed, wrongly added and
		// even transposed characters
		for _, value := range commandsTree.Walk(commandsTree.Root()) {
			if sort.SearchStrings(closestCommands, value) < len(closestCommands) {
				continue
			}
			// 2 is arbitrary and represents the max
			// allowed number of typed errors

	ch := make(chan itemOrErr)

	go func() {
		defer xioutil.SafeClose(ch)

		// Allocate new results channel to receive ObjectInfo.
		objInfoCh := make(chan ObjectInfo)

		if err := objAPI.Walk(ctx, minioMetaBucket, pathPrefix, objInfoCh, WalkOptions{}); err != nil {
			select {
			case ch <- itemOrErr{Err: err}:
			case <-ctx.Done():
			}
			return
		}

		for obj := range objInfoCh {