Wrote 3 networking stacks in the last 5 years. This is the one. Super testable, very nice interface.

Behold, Lneto (github).

I'll be hosting a website powered with a LAN8720 Phy controlled by a RP2040 MAC at http://gsan.whittileaks.com. HTTP ONLY, make sure to remove the s in https:// if your browser adds it automatically. Turn the LED on and off a gusto. Below is the image of the server running in production. Soldered by yours truly. No operating system, true baremetal. Here's the code.

You can find talks I've given on Lneto in this youtube playlist (FOSDEM+GC25).