free_taxi模式中 defenseService.fetchResult 应等队列有数据再rpop数据，否则会response一个空值 <img width="882" height="68" alt="Image" src="https://github.com/user-attachments/assets/8edf992c-62d7-4f1e-a734-6e2c4bfb2f7b" /> <img width="1123" height="667" alt="Image" src="https://github.com/user-attachments/assets/41a86fe0-56fe-4cc1-884e-d03f239c71a3" />
