resume rollback

What does Resume Rollback mean in the Transfer -> Files section in the options?

still don't know what resume rollback is... please someone tell me

maybe only the programmers know... and they're probly saying if we cant figure it out then we dont have use for it ...

this is what the FAQ says

How To force the Rest command

1. Click on Tools > Settings > Transfer > Files -> "Resume Rollback".

2. Set a file size in bytes by typing it in, or use the up/down arrows (1024 bytes recommended).

3. Click the "OK" button and the Rest command will be used instead of the default APPE command.


Welll... samrters .. we dont want to know how to do it.. its plain as daylight in the menu... what is it?? what is it used for ?? what is it good for?? When should I use it ?? how would I know when to use it?? when would I know how to use it??