What is done for that is userspace gets the network data directly without (I believe) involving syscalls. It's not something you'd do for end-user software, only the likes of MOFAANG need it.
In theory the likes of io_uring would bring these benefits across the board, but we haven't seen that delivered (yet, I remain optimistic).
I'm hoping we get there too with io_uring. It looks like the last few kernel release have made a lot of progress with zero-copy TCP rx/tx, though NIC support is limited and you need some finicky network iface setup to get the flow steering working
In theory the likes of io_uring would bring these benefits across the board, but we haven't seen that delivered (yet, I remain optimistic).