I thought you were going to suggest it to be processed like one of those trick exams of reading all of the questions before answering any of the questions where the last question is something so obvious that like stand up sit down, then turn in the test with out writing anything on it. So in this case, read all of the instructions in the packet. If the last is CANCEL, do nothing.
It's basically like that - the "fastest" servers will begin responding before processing the entire packet; but it's likely that's never really needed (and if it is, you'll know and can turn it on) but the smarter thing to do is process the whole packet at once.
