There are many awesome things about the Firefox networking layer. However realtime visibility into what its doing is not on that list.
Thanks to Google Summer of Code, Jiten Thakkar is going to work on that problem this summer. Jiten is already a card carrying Mozillian with code commits in several parts of Gecko and I'm excited to have him focused on necko and an add-on for the next few months.
We hope to learn what connections are being made, how fast they are running, what the DNS cache looks like, how often SPDY is used, and all manner of other information that will aid debugging and inform optimization choices. Maybe even icing on the cake ssuch as in-browser diagnostic tools (e.g. Can I tcp handshake with an arbitrary hostname? How about HTTP? How about SSL?) to round things out.