Simon, that seems to definitely change things, but now the class is totally unusable with the error:
Jobs::HandledExceptionWrapper: Wrapped NameError: uninitialized constant MessageBuilder
I’ve posted a Gist of the changes I made to mimic yours here:
https://gist.github.com/tareko/c94b7dd8a24e9845617e157ec0899e43
Definitely this seems like a step forward, since at least I’m manipulating the class, but not sure what I’m doing wrong here. I will also try to understand @Mittineague 's solution and see if I can implement it.