func (fi *FileInfo) TierFreeVersionID() string {
	return fi.Metadata[ReservedMetadataPrefixLower+tierFVID]
}

// SetTierFreeVersion sets fi as a free-version. This method is used by
// lower layers to indicate a free-version.
func (fi *FileInfo) SetTierFreeVersion() {
	if fi.Metadata == nil {
		fi.Metadata = make(map[string]string)
	}
	fi.Metadata[ReservedMetadataPrefixLower+tierFVMarker] = ""
}

	PreserveETag                        string    // preserves this etag during a PUT call.
	NoLock                              bool      // indicates to lower layers if the caller is expecting to hold locks.
	ProxyRequest                        bool      // only set for GET/HEAD in active-active replication scenario