fix preemptive downloads with ensure_shard

exo/main.py

@@ -134,7 +134,7 @@ def preemptively_start_download(request_id: str, opaque_status: str):
     if status.get("type") == "node_status" and status.get("status") == "start_process_prompt":
       current_shard = node.get_current_shard(Shard.from_dict(status.get("shard")))
       if DEBUG >= 2: print(f"Preemptively starting download for {current_shard}")
-      asyncio.create_task(shard_downloader.ensure_shard(current_shard))
+      asyncio.create_task(shard_downloader.ensure_shard(current_shard, inference_engine.__class__.__name__))
   except Exception as e:
     if DEBUG >= 2:
       print(f"Failed to preemptively start download: {e}")