Why not use an example that actually works?

That paragraph confused me too, but then I realised what he meant, felt the same as you, but still couldn't think of anything on the spot that would work other than:

    set(value) {
        count = 0
        while count != value {
            increment()
        }
    }

(~~may not be~~ probably isn't valid Dart)

That's an infinite recursion, because increment() is going to call back to set()

Heh, true. So, examples are hard. :)