That's an interesting concept... I am not sure if there is an out of the box solution or not? (To be fair, our apps can't run offline, so I've not tried this)
My understanding of the "offline" tracking was that Adobe would continue to run on the app, collecting and storing the data locally, until the user came back online, then the entire bundle would be sent to the server....
I don't know if there is anything attached to the bundled data that would or could be used to identify it as being offline...
However, do you have AEP Assurance (i.e. Griffon) installed in your apps?
If I were you, I would do some testing... first hit a few specific screen as "online", (you should see these immediately in Assurance), then turn off the internet and hit the same pages, then turn the internet back on (which should send the bundle to Adobe...which should then show in Assurance.
Compare the hits really closely to see if there are any differences (aside from the obvious timestamp differences),
You might be able to see if there is some indicator of "offline" and if there is, you might be able to leverage that either directly in Adobe, or possibly map it to a dimension or event using Processing Rules...
If you can't find anything, you may have to see if your developers can get creative.... like can they detect the online/offline status? If so, can they set a dimension (either a context variable to be mapped with processing, or directly into the schema depending on your implementation) that you can use in your reporting?
