Xamarin.Forms - How do I change the background color at random times?

I'd like to change the background color at random times throughout the game level. For example, the player is playing the game on a white background for a couple seconds and then the background color changes to black and stays like that for 1 second, and then goes back to a white screen. Maybe a minute later the screen turns black, changes back to white, and then 2 seconds later it changes to black again.

Basically, how do I change the background color at random times?