Add better logging when tarring empty data
Add better logging when tarring empty data

Summary: This is nice to do as it will tell us if what we're tarring is bad

Reviewed By: c-ryan747

Differential Revision: D14913150

fbshipit-source-id: 9220640bdb78644e8c45c0f730169ec9b56b4009

facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl