Slider should provide a way to report the current value while being dragged

Currently, Slider reports changes of visual position on a continuous basis, but not on value, which is set only when the handle is released. While I understand the rationale behind this choice, it would be good to provide a way to get updated value in real time, for instance if another control depends on it (which is my use case).

I see two ways of doing so:

• provide a property like visualValue
• provide a public method that maps the position to the value