11989.Feature

Added explicit APIs for bytes-returning JSON serializer: JSONBytesEncoder type, JsonBytesPayload, :func:~aiohttp.web.json_bytes_response, :meth:~aiohttp.web.WebSocketResponse.send_json_bytes and :meth:~aiohttp.ClientWebSocketResponse.send_json_bytes methods, and json_serialize_bytes parameter for :class:~aiohttp.ClientSession -- by :user:kevinpark1217.