[Wishlist] Add pause feature to dist-upgrade

It would be helpful, I believe, if there were a pause button on the distribution upgrade window of "update-manager". This would help for people who may have to disconnect from the internet for a certain period of time for some reason or, in my case, their router is crappy and starts failing after keeping constant 200k download rate(Overheats and begins to crumble basically). This 'failing of the router' forces me to cancel the upgrade before it fails or suffer the consequences of having speeds of about 40k all the way down to 0k per second for an extended period of time.

I can, of course, cancel the upgrade and restart it, and it will start where it left off... But it does require me to redownload some upgrade files and takes longer than just pausing the download.

Implementing the pause feature would allow people to disconnect their network connection without having to restart the upgrade program and would save people time in the long run. It would also allow people who have flaky routers, like me, to pause the download and give the router a rest every once in a while.

If implementing this would be difficult, an alternative would be the ability to limit, on the client side, the download speed. While this would slow the download, in the long run it would decrease the total time it takes to get all the packages.

Thanks for taking the time to read this suggestion