The PR adds `_async_input_callback` and `_async_success_callback` for async litellm operations but does not add a corresponding `_async_failure_callback`. If litellm invokes async callbacks for failure scenarios when using `acompletion()` or `aembedding()`, exceptions may not be properly captured and spans may not be closed. The existing tests `test_async_exception_handling` pass, suggesting the sync callback may still be called, but this creates an inconsistency in the callback registration pattern.

The async test patches `client.embeddings._client._client` but calls `litellm.acompletion()`, which uses the completions endpoint. The sync version `test_exception_handling` correctly patches `client.completions._client._client`. This copy-paste error means the mock may not intercept the request properly, potentially causing the test to pass incorrectly or behave inconsistently.