> I noticed that if I go on "Mirror" is the "Pause
> Transfer" But I do not think they ensure proper

On 3.4x versions cancel/continue is broken. This means if you cancel, anything
not already processed will be lost from the cache and will be redownloaded on
Continue or Update.

On the initial Download, just press cancel ONCE, and wait for the current
downloads to finish. There is nothing in the cache to loose.

For updating mirrors, Pause, minimize HTT, hibernate if necessary, resume
later. Do not cancel, do not close application, do not kill it, do not
shutdown/reboot.