Single Step (pause, resume), or externally clock game loop

Just so you don't think we are crazy.

We want to use unity3d to display real-time 3D sensor data (no game players, no user, no physics). Is it possible to put unity3D into pause state (e.g. timescale=0)?

We would want the network messages to still flow, and to be able to update the location, and pitch/yaw/roll of the the objects while in pause. (these messages would be coming in while the game is paused, and there will be a lot of them).

Alternatively, we are looking at a way to single step the engine (ala CesiumJS or GazeboSim) so that we can do a start, and get a end event. (I.e. if I set the timescale=0, can I wait for a network message, set the timescale to run again, and then shut it back to 0, as soon as the frame advances?)

BTW, How would we know that all the rendering update (update of objects are done). Would this be the OnPostRdender event?

http://docs.unity3d.com/Manual/ExecutionOrder.html

(we have hard physical devices, and we cannot rely on the free running clock of Unity3D, we need a true hard external clock).