Default Download booster

Quick question to those who are in the know with these matters, would it be possible to port over this feature used on the S5?

I like the look of this. On the same lines, how easy, if at all possible, would it be to create a mod which could for instance allow you to download via wifi and at the same time browse/use an app via 3/4G...our vice versa?

Xperia Z