fix by patrace's comments

Signed-off-by: Lizhi Zhou <[email protected]>

Author: reasonsolo

tensorrt_llm/serve/cluster_storage.py

@@ -91,7 +91,7 @@ async def delete(self, key: str) -> bool:
     async def watch(self, key_prefix: str) -> WatchEventQueue:
         ...
 
-    # unwatch the key prefix, if the key prefix is not in the watch list, raise an error
+    # unwatch the key prefix, if the key prefix is not in the watch list, raise a KeyError
     async def unwatch(self, key_prefix: str) -> None:
         ...
 
@@ -452,6 +452,14 @@ def _get_lease(self, key: str, ttl: int = -1) -> etcd3.Lease:
     def client(self):
         return self._client
 
+    async def start(self):
+        # nothing to do
+        ...
+
+    async def stop(self):
+        # nothing to do
+        ...
+
     async def set(self,
                   key: str,
                   value: str,