final boolean isObject = data instanceof ObjectData;
final String tag = isObject ? "isis" : "collection";
writer.write("<");
writer.write(tag);
final RootOid oid = data.getRootOid();
Utils.appendAttribute(writer, "oid", oid.enString(getOidMarshaller()));
Utils.appendAttribute(writer, "user", "" + getAuthenticationSession().getUserName());
final long sequence = data.getVersion().getSequence();
final String sequenceString = Long.toHexString(sequence).toUpperCase();
Utils.appendAttribute(writer, "ver", "" + sequenceString);