[Fix] guard get_proxy_server_request_headers and bound atexit flush

- get_proxy_server_request_headers raised AttributeError when
  litellm_params["proxy_server_request"] was set to None (the default
  for SDK callers). Guard the helper so it returns {} for None or
  non-dict values.
- LoggingWorker._flush_on_exit now wraps each queued coroutine in
  asyncio.wait_for(..., timeout=2.0) so a single hung coroutine cannot
  block the atexit handler past the outer 5s budget.
- Drop _turn_on_debug() from test_vertex_schema_test to reduce noise on
  a network-dependent test.

litellm/litellm_core_utils/llm_request_utils.py

@@ -77,8 +77,8 @@ def get_proxy_server_request_headers(litellm_params: Optional[dict]) -> dict:
     if litellm_params is None:
         return {}
 
-    proxy_request_headers = (
-        litellm_params.get("proxy_server_request", {}).get("headers", {}) or {}
-    )
+    proxy_server_request = litellm_params.get("proxy_server_request") or {}
+    if not isinstance(proxy_server_request, dict):
+        return {}
 
-    return proxy_request_headers
+    return proxy_server_request.get("headers") or {}

litellm/litellm_core_utils/logging_worker.py

@@ -507,11 +507,13 @@ class LoggingWorker:
                 except asyncio.QueueEmpty:
                     break
 
-                # Run the coroutine synchronously in new loop
-                # Note: We run the coroutine directly, not via create_task,
-                # since we're in a new event loop context
+                # Run the coroutine synchronously in new loop with a per-task
+                # timeout so a single hung coroutine cannot block the entire
+                # flush past the outer time budget.
                 try:
-                    loop.run_until_complete(task["coroutine"])
+                    loop.run_until_complete(
+                        asyncio.wait_for(task["coroutine"], timeout=2.0)
+                    )
                     processed += 1
                 except Exception:
                     # Silent failure to not break user's program

tests/local_testing/test_amazing_vertex_completion.py

@@ -3688,7 +3688,6 @@ def test_vertex_ai_llama_tool_calling():
 
 def test_vertex_schema_test():
     load_vertex_ai_credentials()
-    litellm._turn_on_debug()
 
     def tool_call(text: str | None) -> str:
         return text or "No text provided"