How to use the colors?

[RaoulNL]

Hi,

Say I want to start the progress at the top. The progress color should begin with a light grey color and end with an (e.g.) red color when it has reached up to 360 degrees.
My question is how would I set this up?
startAngle would be -90.
clockWise would be true

But what would be the values for gradientRotateSpeed and the colors?
My best effort is:
gradientRotateSpeed = 0.25
colors: [.lightGray, .red]

I want to get as close as possible to the effect on the examples page with the orange progress bar.
Any help is greatly appreciated.