Seaf-fsck export sync / incremental

I have been looking at using the seaf-fsck --export feature. How does it handle exporting multiple times to the same location? Does everything get overwritten, every time?

What I would like is to be able to export in rsync fashion. When dealing with terabytes of data, it makes a big difference if the export operation can skip files that already exist and are up-to-date.

Is it possible for export to get the modified date for files, as it retrieves them? That would be a first step.