Major Description
BlockPoolSliceScanner uses Time.now to calculate an interval. But this is incorrect, since if the wall-clock time changes, we will end up setting the scan periods to a shorter or longer time than we configured.
There is also a case where we may divide by zero if we get unlucky, because we calculate an interval and divide by it, without checking whether the interval is 0 milliseconds. This would produce an ArithmeticException since we are using longs.