[Feature Request] Option to write file name to stdout after transfer completes

[GyrosGeier]

I have a few processing pipelines, where I currently ingest files using

rsync remote:/incoming ./ & rsync=$!
while kill -0 $rsync; do sleep 20; ls | xargs -P`nproc` -n1 process_file; done

That is a lot of scripting, and it processes files in separate batches with a few seconds of pause in between. I'd rather do something like

rsync remote:/incoming ./ --output=completed | xargs -P`nproc` -n1 process_file

For that I'd need a mode where the names of files are written to stdout, but only after transfer is completed.

What would be extra cool would be a mode using NUL bytes as separators.