How to initialize the clock after viewer initialization?

I see when you first initialize the viewer, you can set the clock, but my problem is I dont know the start and stop time until my request for the start and end time completes.
Is it possible to:

1- Create/initialize a new Cesium.Clock after viewer is created?

2- Set the startTime and stopTime on the cesium.viewer clock after the Cesium.Viewer is initialized?

3- Any setters on the startTime, currentTime, and stopTime of the clock?

No on 1, but yes on 2 and 3, you can set the viewer.clock properties at any time you like.