type WalkOptions struct {
	Filter       func(info FileInfo) bool // return WalkFilter returns 'true/false'
	Marker       string                   // set to skip until this object
	LatestOnly   bool                     // returns only latest versions for all matching objects
	AskDisks     string                   // dictates how many disks are being listed

		}
		for _, prefix := range prefixes {
			prefixResultCh := make(chan itemOrErr[ObjectInfo], workerSize)
			err := api.Walk(ctx, r.Bucket, prefix, prefixResultCh, WalkOptions{
				Marker:       lastObject,
				LatestOnly:   false, // we need to visit all versions of the object to implement purge: retainVersions
				VersionsSort: WalkVersionsSortDesc,
			})
			if err != nil {
				cancelCause(err)
				xioutil.SafeClose(results)