src/Tracker.php
public function getNumProcessedItems($tickType = null)
    {
        if (null !== $tickType) {
            return (array_key_exists($tickType, $this->numProcessedItems))
                ? $this->numProcessedItems[$tickType]
                : 0;
        }
        else {
            return array_sum($this->numProcessedItems);
        }
    }
public function getNumProcessedItems($tickType = null)
    {
        if (null !== $tickType) {
            return (array_key_exists($tickType, $this->numProcessedItems))
                ? $this->numProcessedItems[$tickType]
                : 0;
        }
        else {
            return array_sum($this->numProcessedItems);
        }
    }
Return the number of items processed, including failed/succeeded

@param int $tickType  Tick::SUCCESS, Tick::FAIL, Tick::SKIP, or null for all
@return int