* Else, @delta is a progress delta since the last call, as a fraction
* of @max. I.e. the delta is @delta * @max / 100. This allows
* relative accounting of functions which may be a different fraction of
* Else, @delta is a progress delta since the last call, as a fraction
* of @max. I.e. the delta is @delta * @max / 100. This allows
* relative accounting of functions which may be a different fraction of