What should the deltaTime passed to a window's render event handler specifically be used for?

[jameswilddev]

When I'm setting up events for a window both the Update and Render event handlers take a delta time as an argument (which appears to be in seconds):

window.Update += (double deltaTime) => 

window.Render += (double deltaTime) => 

While I understand that the Update event handler should be used to advance my simulation/game state, what is intended use of the delta time passed to the Render event handler?

It looks like both delta times are approximately 1/60th of a second when v-synced to 60Hz, so I don't think I should be advancing my simulation/game state in Render, but the figure is slightly different to the preceding Update implying that I should be doing something with it and it's not just a copy of the value passed to Update for convenience:

UPDATE 0.0180284
        RENDER 0.0179364
UPDATE 0.014816
        RENDER 0.0148439
UPDATE 0.0158521
        RENDER 0.0158707
UPDATE 0.018426
        RENDER 0.0184124
UPDATE 0.0141756
        RENDER 0.0141088
UPDATE 0.0183295
        RENDER 0.0183297
UPDATE 0.0153938
        RENDER 0.0155264
UPDATE 0.0169727
        RENDER 0.0168674
UPDATE 0.0165973
        RENDER 0.0166093
UPDATE 0.0168816
        RENDER 0.0168227

I don't think there's a bug or anything here I'm just not quite clear on what the API is trying to communicate to me.

[Perksey]

The delta times for both events is the number of seconds since that particular event has been raised. Update precedes Render always.

[jameswilddev]

Ah I see thanks. I'll just use Render's then rather than trying to combine the two.