void
rrToWire(DNSOutput out, Compression c, boolean canonical) {
	out.writeU16(covered);
	out.writeU8(alg);
	out.writeU8(labels);
	out.writeU32(origttl);
	out.writeU32(expire.getTime() / 1000);
	out.writeU32(timeSigned.getTime() / 1000);
	out.writeU16(footprint);
	signer.toWire(out, null, canonical);
	out.writeByteArray(signature);
}
Returns the binary data representing the signature
src/main/java/core/org/xbill/DNS/SIGBase.java