Comment 4 for bug 306979

No pause button no. Note that if you "Resume Later", it shouldn't be actually starting over. It may look like it, because it rescans files and starts progress at 0%, but it will be building on previous progress and should move to 100% faster because there is less work to do.

The problem here is that there doesn't seem to be very good ways of throttling bandwidth. Like a network nice or something. Trickle is the closest I've seen, but it's not a very common tool, not sure how good it is.