@K2Your best bet is to capture the traffic and save it to a file using the following link.
Once you have the file saved then transfer it to your PC/laptop/server and decrypt the traffic using wireshark and the following link.
I don't believe you can really do this any other way that is clean.
In general good information, but the question is here how to get that key log file information. For a health monitor you don't really seem to have a way.
You can just do curl with the same content. Else perhaps have a look at the server logs?