Function _sse_with_checkpoints

fastapi/routing.py:613–621

(
                    stream: ObjectReceiveStream[bytes],
                )

                async_exit_stack.push_async_callback(sse_receive_stream.aclose)

                async def _sse_with_checkpoints(
                    stream: ObjectReceiveStream[bytes],
                ) -> AsyncIterator[bytes]:
                    async for data in stream:
                        yield data
                        # Guarantee a checkpoint so cancellation can be
                        # delivered even when the producer is faster than
                        # the consumer and receive() never suspends.
                        await anyio.sleep(0)

                sse_stream_content: AsyncIterator[bytes] | Iterator[bytes] = (
                    _sse_with_checkpoints(sse_receive_stream)