data.volumeId    = volumeId;
        public UnderlyingData duplicate(int newId, int newFolder) {            UnderlyingData data = new UnderlyingData();            data.id          = newId;            data.type        = type;            data.folderId    = newFolder;            data.parentId    = parentId;            data.indexId     = indexId;            data.blobDigest  = blobDigest;            data.date        = date;            data.size        = size;            data.flags       = flags;            data.tags        = tags;            data.subject     = subject;            data.volumeId    = volumeId;            data.unreadCount = unreadCount;            return data;        }