I have some question about nft fixed price sale. what I know is that if user send two transactions, one to his own nft and the other to the marketplace contract, the tx to nft occur ownership transfer to nft_sale_contract, and the tx to marketplace occur the deployment of nft_sale_contract.

but how can I be sure that deployment of nft_sale_contract precedes? I know that in TON we can't predict which tx will arrive first, and ths nft_sale_contract will occur an error if the nft ownership assignment precedes the deployment.

how the getgems or other marketplace control such a condition?