void rrToWire(DataByteOutputStream out, Compression c) throws IOException {
if (key == null && (flags & (FLAG_NOKEY)) != (FLAG_NOKEY)) return;
out.writeShort(flags);
out.writeByte(proto);
out.writeByte(alg);
if (key != null) out.write(key);
}
void rrToWire(DataByteOutputStream out, Compression c) throws IOException {
if (data != null) out.write(data);
}