ESP32 and ENC28J60 - connect to lwip stack

[Arthedian]

Hello,
I am trying to conect ESP32 and ENC28J60. I already found two functions (in "tcpip_adapter.h") - "tcpip_adapter_eth_start" and "tcpip_adapter_eth_input". But the problem is that I didnt found function, from which I get output packet, which I need send to ENC28J60. How should I get the packet?