When T-Mobile CEO John Legere made his predictions for 2015, he forecast that AT&T would copy T-Mobile's Data Stash . And sure enough, it looks like Legere's prediction will come true. A leaked image featuring actress Milana Vayntrub portraying sarcastic AT&T rep Lilly Adams, indicates that the nation's second largest carrier will soon be offering rollover data.We don't have any information about AT&T's plan. T-Mobile's Data Stash allows those Simple Choice customers receiving 3GB or 5GB of the sweet stuff each month, to take the amount of unused data and roll it over for use anytime over the next 12 months . To get its subscribers started, T-Mobile gave Data Stash members 10GB of free data. That block of data must be used up completely before the rollover process starts.AT&T has been sending out memos here and there, hinting that they have some more exciting news to pass along at CES. Rollover data will apparently be one of those announcements. The leaked image comes from one of our loyal readers who remains anonymous because he claims to work for AT&T.Thanks for the tip!