Condition update failure due to a backend error should be a Nack

[joelrebel]

To mark and event that could be processed because of a backend error the event should be nak'ed, based on the Jetstream docs, it should be an AckTerm

AckTerm - Instructs the server to stop redelivery of a message without acknowledging it as successfully processed

For this we need to add support in the events library to send an AckTerm

_Originally posted by @DoctorVin in #26 (comment)