I have a corner case that seems like it makes sense. Say my bandwidth is limited by my provider (be it local, mobile phone, VPS, or wherever I might want to do this). Overages are outrageously expensive. I have a lot of data that I want to rsync, like uh, pictures. Stuff that doesn't change often, but could potentially cause some significant churn (say I make a bunch of thumbnails for an album or something, or change a bunch of exif data).
Since bandwidth can be so expensive if I run into overages, and I'm rsyncing data that totals to more than my monthly limit, and I'm in no big hurry, I'd like to spread this out. Right now, I have to selectively choose what to rsync, or babysit the process and kill it at the right time. This is all very troublesome, especially if I want to automate this particular rsync job.
It seems like an rsync option that lets me choose a maximum amount of data to transmit in a single session is what I need. The man page doesn't seem to show anything to this effect. Is there possibly some hidden or undocumented option that exists that would help?