Other than reading the code, do you have some tutorial to explain how to consume the exported data and correlate them with the corresponding workflow instance/tasks?
I was hoping you have some high level APIs for this type of operations.
Start the broker with the debug exporter enabled and you will see the data that is exported. You can probably figure out how you would do what you want to do from that.
Or use the ElasticSearch Exporter and query the ES server. I don’t know how to do that, but it is an easy Google search and a well-defined problem / solution space.