It's clear that you're coming out with this old chestnut again and are happy like a little kid who got a lollipop because "Deino was wrong once, so he's always wrong and never sees it; LOL" ... I would just be happy if you would smile at the other fan-boy homies as much as you do at me, who have been proudly announcing for years that "Pakistan gets everything, J-15, J-16, J-20, Eurofighter ... brrrother I tell you"!
But just use your brain for a moment, what could possibly be the reason for China to buy the Su-57? Technically and operationally NOTHING ... at best another political concession.
Well, a high-ranking military or political exchange at an Airshow is common business ... that's in no way a hint, China will get it! And I'm sure they have enough other topics to discuss.