What was the problem?
The CSV streaming functionality wasn't working because it required per-message streaming to be enabled, but the code only automatically enabled this when using --streaming-output-json. When using only --streaming-output-csv, the per-message streaming flag wasn't set, so no data was written to the CSV files.

What needs to be fixed:
modify the enable_csv_streaming() method in /root/sandbox/rusty-comms/src/results.rs to automatically enable per-message streaming when CSV streaming is requested.