}
}
```

## 9. Performance and Optimization

### 9.1 Witness Event Batching
```java
public class WitnessEventBatcher {
    private final Queue<WitnessNotification> pendingNotifications;
    private final ScheduledExecutorService scheduler;
    private final int batchSize = 10;
    private final long batchTimeout = 100;  // 100ms
    

            urlFilterService.delete(sid);
        } catch (final Exception e) {
            logger.warn("Failed to delete UrlFilter: sessionId={}", sid, e);
        }

        try {
            // clear queue
            urlQueueService.clearCache();
            urlQueueService.delete(sid);
        } catch (final Exception e) {
            logger.warn("Failed to delete UrlQueue: sessionId={}", sid, e);
        }

    /** Array of supported file protocols for URL classification. */
    protected String[] fileProtocols = { "file:", "smb:", "smb1:", "ftp:", "storage:" };

    /** Queue to track the current XML element hierarchy during parsing. */
    protected LinkedList<String> tagQueue;

    /** List to store parsed label types for access control. */
    protected List<LabelType> labelList;