How much data transferred over wifi or 2G/3G?

Hello kind people of the internet,
apologies in advance if this question has been asked before, or if this is answered somewhere in the documentation…if so, puhlease point me to a proper link.

I’d like to know approximately how much data is being transferred over the wireless interface, or perhaps how to guestimate how much data is being sent/used/consumed over the wireless interface

…such as:

A-When uploading/flashing a program to the core? (let’s assume perhaps a 500 line program)…is there some sort of per-line ‘metric’ that could help gauge how much data is being transferred when a program is uploaded/flashed?

B-When the core is simply “slow breathing cyan”?..or ‘flashing green’?..(I’m assuming that some data ack/nak is taking place back to the Particle mother-ship).

C.-Perhaps, when reading some simple temperature measurements from the core from a temperature guage?

D.-Will there be (or is there already) a “dashboard” that shows data-usage to/from the core? (note: Google API’s have a dashboard showing data usage).

Oh the one hand, I do realize that Particle handles all that “under-the-hood” complexity for me so that ostensibly I can concentrate on solutions rather than nuts-n-bolts.

However, I feel like I’m kinda working ‘blind’ not really knowing how much data is traversing over the ether?
…especially when I start working with the 2G electron…and hate the feeling of being a ‘cargo-cult’ programmer (which sad to say: is much of the time: as when it all works it’s simple magic)…but when things go wrong (as oft they do) it helps to have some rudimentary understanding how the machine actually works.

thanks mucho in advance