[Core] v1: Use atexit to handle engine core client shutdown (vllm-pro…

…ject#11076)

Signed-off-by: Russell Bryant <[email protected]>

vllm/v1/engine/core_client.py

@@ -1,3 +1,4 @@
+import atexit
 import multiprocessing
 from typing import List, Union
 
@@ -157,6 +158,7 @@ def __init__(
             should_shutdown=self.should_shutdown,
             **kwargs,
         )
+        atexit.register(self.shutdown)
 
     def shutdown(self):
         # Send shutdown signal to background process.