Mozilla does this to great effect:
It does need to be paired with something that can capture and display the NetFlow data well. But with that, you can literally see what data is going where in your network, accurate to the byte. And with a good visualisation solution, you have the data historically too, so you can (easily) match things up time wise.
eg a developer writes a bad query which pulls 1/2 the database over the network to the front end server for filtering results there, instead of filtering them in the database. You can see that on the network fairly easily, and let the developer self-educate (if given access to the tools). ;)
As an aside, the gold standard used to be a commercial product called "NetFlow Tracker". It was amazing (fond memories), but the company behind it (Fluke Networks) didn't seem to know anything about software sales. So, it's now discontinued. :(
Hopefully there's a modern version of that somewhere. :)
If you would like to follow progress you can dive into it all here [1]. One of the spearpoints is Gitaly, which should significantly improve git access.
[0]: http://monitor.gitlab.net/dashboard/db/fleet-overview?from=n...
[1]: https://gitlab.com/gitlab-com/infrastructure/issues/947
