Xamarin SerializeObject returns {}

[cboyce428]

Xamarin.Forms project when serializing an object the json returned is "{}" when running via the live player (android):

[Preserve(AllMembers = true)]
[JsonObject(MemberSerialization.OptOut)]
public class Author
{
    public int Id;
    public string Name;
}

        Author mmm = new Author
        {
            Id = 100,
            Name = "asdjasd"
        };
        string json = JsonConvert.SerializeObject(mmm);

        DisplayAlert("Dialog Title", json, "Ok", "Cancel");

Originally reported here:
https://stackoverflow.com/questions/48041823/jsonconvert-serializeobject-always-return-in-xamarinforms

[cboyce428]

This appears to be a problem with the live player, if I compile it to an APK it works fine on the actual device.