Go's http server. The inside of nginx is an incredible mess of C. I begrudgingly trust it since it is being actively attacked and maintained. The inside of Go's http server is incredibly clearly written. I am confident that it too will be maintained. And it's roughly half the speed of nginx, which is plenty fast. (Few web application servers in the world are sitting there with nginx using all the CPU.)
It's a long slow process partially precisely because I intend to do this carefully, and discarding nginx is not something to be taken lightly, but long term, as I said, I want the C out of my stack.
That's interesting because I'm seeing people do the exact opposite : since almost all security holes in web environments these days come not from the applications but the myriad of frameworks and unauditable layers making fun use of objects all over the place, now using C or even ASM is the only way to limit the moving parts and to ensure that your code base doesn't change between two audits.
It's a long slow process partially precisely because I intend to do this carefully, and discarding nginx is not something to be taken lightly, but long term, as I said, I want the C out of my stack.