Implementation details of of proxying?

[Jeffrey Walton <noloader@xxxxxxxxx>]

I'm looking for the implementation details of how squid proxies its
connections. That is (in pseudo code):

    socket src = ... // client socket
    socket dest = ... // server socket

    int n = read(src, buffer)
    write(dest, buffer, n)

I imagine its not that naive, and I'm really interested in the
techniques squid uses to improve performance around that locus.

I'm having trouble locating the reads and the writes in the source
code. I did not see anything that looked right in comm.cc, forward.cc,
and a few other candidates.

Would anyone know where to find squid's implementation of the read/write cycle?

And a link to a paper on squid's study of the problem would be great.
I did not see it on the website. (Would the NSF work still be
relevant?)

Thanks in advance.