void testBinaryConstructorAndToByteArray() {
            // Arrange: revision=1, count=2, identAuth zeros except last byte, subauth 10, 20
            byte[] ident = new byte[] { 0, 0, 0, 0, 0, 5 };
            rpc.sid_t st = buildSidT((byte) 1, ident, 10, 20);

            byte[] bytes = SID.toByteArray(st);

            // Act: construct from bytes and re-encode
            SID sid = new SID(bytes, 0);