@app.get("/stream-jsonl")
async def stream_jsonl() -> AsyncIterable[int]:
    """JSONL async generator with no internal await."""
    i = 0
    while True:
        yield i
        i += 1


async def _run_asgi_and_cancel(app: FastAPI, path: str, timeout: float) -> bool:
    """Call the ASGI app for *path* and cancel after *timeout* seconds.

    Returns `True` if the cancellation was delivered (i.e. it did not hang).
    """