Setting extended attributes right after rsync prints a filepath on stdout

[dv1]

I want to set extended attributes for each file that rsync transferred. I run rsync with the --out-format=%i %C %n switch to get a checksum, and that is what I want to store in the extended attributes. Right now, I just store rsync's stdout into a temporary file, and read that afterwards. But I figure that it would be better to just set the extended attribute on the fly. I'd do something like this:

rsync --out-format="%i %C %n" source/ dest/ | while read line; do
  checksum=$(echo "${line}" | awk '{print $2}')
  filepath=$(echo "${line}" | awk '{print $3}')
  setfattr -n user.checksum -v "${checksum}" "${filepath}"
done

However, I am not sure if this is safe. Once rsync prints out a line for a transferred file, is it 100% done with that file? Or could setting an extended attribute somehow mess up its operations? Or does rsync touch the files later somehow, potentially erasing the extended attribute?