Feature Request: puzzle timer

It would be really nice to have the option to display a timer that counts up, just to be aware of how much time I'm spending on each puzzle. Ideally, it would not be distracting at all, and I certainly wouldn't want it to affect rating. Maybe it would also be cool to keep track of the amount of time it takes to solve each puzzle, so I could see what my average time is and which types of puzzles take me longer. I really like the timer on chesstempo.com/chess-tactics/

The timer should be toggleable in settings and should automatically disappear in zen mode.
It could also be a new statistic in "Puzzle Dashboard".
For example: average time per puzzle, average time per certain puzzle tactic, average time for correct puzzle, average time for incorrect puzzle.