FlamingockLockAdapter.held()  = true
FlamingockLockAdapter.fence() = -1   (UNFENCED = -1)

[검사가 마이그레이션을 보기 전에 걸린다]
  마이그레이션 0건 -> 거절, MongoOperationRejectedException
      this migration lease exposes no fencing token, so a stalled runner cannot be excluded; use a fenced lease or run the migration inside a maintenance window with the application stopped
  재개 불가 1건 -> 거절, MongoOperationRejectedException
      this migration lease exposes no fencing token, so a stalled runner cannot be excluded; use a fenced lease or run the migration inside a maintenance window with the application stopped

[같은 마이그레이션, 펜스가 있는 리스]
  재개 불가 1건 -> 실행, 결과 1건 COMPLETED