Access starlette response in middleware

middleware.py

class JsonResponseMiddleware(BaseHTTPMiddleware):

    # BaseHTTPMiddleware returns a streaming response that can't be consumed in the middleware
    # Instead we consume it here and create a JsonResponse that can be consumed multiple times

    async def call_next(self, request: Request) -> Response:
        loop = asyncio.get_event_loop()
        queue = asyncio.Queue()  # type: asyncio.Queue

        scope = request.scope
        receive = request.receive
        send = queue.put

        async def coro() -> None:
            try:
                await self.app(scope, receive, send)
            finally:
                await queue.put(None)

        task = loop.create_task(coro())
        message = await queue.get()
        if message is None:
            task.result()
            raise RuntimeError("No response returned.")
        assert message["type"] == "http.response.start"

        body = (await queue.get())['body'].decode()
        task.result()

        response = JSONResponse(
            status_code=message["status"], content=json.loads(body)
        )
        response.raw_headers = message["headers"]
        return response