assertTrue(msg.hasOptionalSfixed64());
msg.clear();
assertFalse(msg.hasOptionalSfixed64());
msg.setOptionalSfixed64(-123);
byte [] result = msg.toByteArray();
int msgSerializedSize = msg.getSerializedSize();
//System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
assertTrue(msgSerializedSize == 9);
assertEquals(result.length, msgSerializedSize);