Likely Wireshark-esque traffic logging of his iPhone/iPad through a proxy.

is there a good proxy app for Mac?

I used Charles a while back, really liked it http://www.charlesproxy.com/

Mitmproxy is also good. Though a hassle to set up, due to some outdated dependencies. Prime target to be packaged up in a docker file.

Charles is usually the best answer unless you are writing an app then the pony debugger from square is really a great tool.

Really clever way to get traffic towards Rjmetrics, love the approach.