Function wrap_py_llm_stream_exec_fn

crates/python/src/py_callable.rs:745–772

Wrap a Python async generator `(LlmRequest) -> AsyncIterator[Any]` for LLM stream execution. The returned future resolves to a Rust stream backed by a Tokio task that repeatedly awaits `__anext__()` and forwards JSON-converted chunks through a channel.

(
    py_fn: Py<PyAny>,
)

/// repeatedly awaits `__anext__()` and forwards JSON-converted chunks through a
/// channel.
pub fn wrap_py_llm_stream_exec_fn(
    py_fn: Py<PyAny>,
) -> Box<
    dyn Fn(
            LlmRequest,
        ) -> Pin<
            Box<
                dyn Future<
                        Output = FlowResult<Pin<Box<dyn Stream<Item = FlowResult<Json>> + Send>>>,
                    > + Send,
            >,
        > + Send
        + Sync,
> {
    let py_fn = std::sync::Arc::new(py_fn);
    Box::new(move |request: LlmRequest| {
        let py_fn = py_fn.clone();
        Box::pin(async move {
            let async_iter: Py<PyAny> = Python::attach(|py| {
                let py_req = PyLLMRequest { inner: request };
                py_fn
                    .call1(py, (py_req,))
                    .map_err(|e: PyErr| FlowError::Internal(e.to_string()))
            })?;
            stream_from_async_iter(async_iter)
        })
    })
}

/// Wrap a Python callable `(Any) -> None` as a collector for streaming LLM calls.
///