func (fu *folderUpload) UnmarshalBinary(b []byte) error {
fu.DataSize = [2]byte{b[0], b[1]}
fu.IsFolder = [2]byte{b[2], b[3]}
func (fu *folderUpload) UnmarshalBinary(b []byte) error {
fu.DataSize = [2]byte{b[0], b[1]}
fu.IsFolder = [2]byte{b[2], b[3]}