That’s not really true in traditional HFT because resting orders no matter how slowly placed will take precedence over orders that are new.
Typically you’d have some combination of order fill for orders that cross the book, successful cancellation (which is where the real race is) and mechanical observation of tick to trade.
Typically you’d have some combination of order fill for orders that cross the book, successful cancellation (which is where the real race is) and mechanical observation of tick to trade.