public function getStats()
    {
        if (null !== $this->errorStack) {
            throw new \RuntimeException(sprintf(
                'Cannot retrieve stats when an exception was encountered ([%s] %s)',
                $this->errorStack->getTop()->getClass(),
                $this->errorStack->getTop()->getMessage()
            ));
        }

        if (false === $this->computed) {
            throw new \RuntimeException(
                'No statistics have yet been computed for this iteration set (::computeStats should be called)'
            );
        }

        return $this->stats;
    }