fix persistent term error, refactor version to match broadway

[mithereal]

this should fix the persistent term error that blows up appsignal when it doesnt exitst, also add ets as an option to persistent term

[josevalim]

Thank you! Can you please expand on why? :) Why would the persistent term not exist?

[mithereal]

maybe its a misconfiguration on my part, but i have a custom producer created, it was working before the 0.7 version, persistant term started throwing in my appsignal, if there is no data in the persistant term table it throws a stack trace, are there any examples on how to acieve this w/o throwing the error. or how to setup a custom prodicer, i cased out the stack trace b/c theres nothing i can find wrong with my producer and it seened like a false positive
also isnt using persistent term less performant than using ets, due to reindexing, thats why i included both ooptions

[josevalim]

I see. To answer those questions, I will need more information about the error, Erlang version, and how to reproduce it, so we can decide how to move forward. Otherwise we shouldn’t merge this patch. :)