OPTIONS via package:http

Hello Ryan,

https://github.com/rknell/alfred/blob/32e30393c9d49965b29553fbbfc9a9f3130538fe/test/alfred_test.dart#L165-L166

fyi

      final response = await Response.fromStream(
        await http.Client().send(
          http.Request("OPTIONS", Uri.parse("http://localhost:$port/test")),
        ),
      );
      expect(response.body, "test string");