W5500 client - what is the Best way to receive large file from server

Hello experts:
I would like to get 64k bytes file from server and save it to memory while in receiving process.
I am looking for the most efficient way to do it.
Is some kind of “flow control” needed?
Is Sn_RX_RSR has a stable value to be used for the receive proc?
How the RX buffer handled to get large amount of data?
Please advise…