I assume you're talking about the code in here? https://github.com/FundingCircle/jackdaw/blob/master/src/jackdaw/streams/mock.clj The intention is to let you provide the data as edn and have it automatically serialized and deserialized through the serdes. That allows your code to not care about the format of the input topic.
thanks
Is there an example anywhere on how to change the DeserializationExceptionHandler in jackdaw?