实现素材预下发优先队列

solve()

Download priority queue:
  Total queued: 16
  DL-00035 SCR-0119 CRV-0007 retry=0 size=10.1MB score=69.9
  DL-00027 SCR-0129 CRV-0006 retry=1 size=8.6MB score=61.4
  DL-00075 SCR-0097 CRV-0105 retry=2 size=0.9MB score=59.1
  DL-00054 SCR-0058 CRV-0011 retry=1 size=18.3MB score=51.7
  DL-00088 SCR-0077 CRV-0018 retry=0 size=30.2MB score=49.8
Status distribution: {'completed': np.int64(76), 'failed': np.int64(9), 'pending': np.int64(7), 'retrying': np.int64(8)}