By reading the Stopwatch documentation, it looks like it does not need disposing of. But similar classes like Timer and Ticker do.
I think I have the right answer but because it didn't feel 100% right to me, I just wanted to hear someone else's opinion! Thank you!
Timer and Ticker register callbacks. If you don't explicitly dispose of them, those callbacks will still be registered somewhere (and therefore will still retain a reference to the Timer/Ticker objects, preventing them from being garbage collected), and the callbacks will still be invoked eventually if you wait long enough.
Stopwatch is completely different. It's just a convenience class to store a starting time and to compute a time difference. There are no callbacks involved. You can just let it be garbage collected.
