## What happened

In `ResponsesAPIStreamingIterator`, the success-logging path schedules `logging_obj.async_success_handler(...)` via a bare `asyncio.create_task(...)` whose returned `Task` is **never stored anywhere**.

Per the asyncio docs, the event loop keeps only a *weak* reference to tasks, so an un-referenced task "may get garbage collected at any time, even before it's done." Under load — or when the client connection closes right after the stream ends — this success-logging task can be collected before it finishes, and the spend-log row is then silently never written. The HTTP response to the client is unaffected, so the loss is invisible from the outside.

## Where

`litellm/responses/streaming_iterator.py` (current `main`, commit `dcf1b445e6`, v1.90.0).

`_log_completed_response()` — the spend-log success handler, **no reference kept**:

```python # ~line 322 asyncio.create_task( self.logging_obj.async_success_handler( result=logging_response, start_time=self.start_time, end_time=end_time, cache_hit=self._completed_response_cache_hit, ) ) ```

Same pattern at ~line 1348 (WebSocket responses success path):

```python asyncio.create_…