Method modified_send

tests/test_routing.py:1004–1007

(msg: Message)

        async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
            async def modified_send(msg: Message) -> None:
                if msg["type"] == "websocket.accept":
                    msg["headers"].append((b"X-Test", b"Set by middleware"))
                await send(msg)

            await self.app(scope, receive, modified_send)