Hi,
We dont have any Api to give turn time.We do notify users by calling onMoveCompleted event when turn gets completed .If you need turn time just to diplay it on the screen then the recommended way is local timer method,In this case dont take any decision in game on local timer basis,Use it to for time display only.
If you want turn time to take any decision in game you should use our AppWarpS2 On Premise solution.In this you can write your own logic on server side which will give you turn time.