Maybe a good idea creating a stop button, I explain.
When users click that button, will receive a dialog with two options: stop now or wait to downloads finish.
If user chooses the first option, all downloads must be interrupted at that moment.
If user chooses the second option, FRD will finish current started downloads and no new downloads should start until users click "Start all". All downloads paused may be marked with orange state, like on picture
When the user clicks "start all", downloads in orange should download again.
What do you think?
Sorry about bad title