With no afterlife how would you logically know you had died?

If there was no afterlife how would you know you were dead? If the moment you died you just faded into oblivion or jetted off to the great white zephrum you would not know you were dead. You would see the Mack truck skidding towards you and thinking you have to get out of its way or you’d be killed, but once it smacks you turning your vehicle into a coaster with wheels you won’t know it, you are dead already. Same as if you were on a roller coaster and a freak accident happens where the harness breaks and you and sever others are launched from the car like Roman candles, you will know you were flying 30ft above the ground, you might even have time to think of how you can land and where, then you will see the ground or whatever was in front of you close rapidly then nothing. Even if you survived the hit and was laying there like a puzzle with many missing pieces dying why would you fret it? Your breathing might get more labored, your body may go numb and cold but the moment your heart stops and your brain shuts down that particular moment you will not even know because once it happens you exist no more. And if you exist no more how would you know you had died logically?