simple example: ```python from graphql_ws.aiohttp import AiohttpSubscriptionServer from .schema import schema subscription_server = AiohttpSubscriptionServer(schema) async def subscriptions(request): ws = web.WebSocketResponse(protocols=('graphql-ws',)) await ws.prepare(request) # payload = request.get('payload') ??? await subscription_server.handle(ws, request_context=payload) return ws app = web.Application() app.router.add_get('/subscriptions', subscriptions) web.run_app(app, port=8000) ``` How to get payload when init connection to socket? ``` {"type":"connection_init","payload":{"FOO":"BAR"}} ```