pause is bugged. says canceled and doesnt allow to resume. but download actually is not canceled and can be resumed in the browser's default manager.

poronga

There is no sense to use this until you made it like status bar.
Here's example https://addons.mozilla.org/ru/firefox/addon/download-status-bar/?src=userprofile

there is no difference to firefox browser downloader. no multi-threading. normal browser also can pause.

When trying to pause a download it gets cancelled

Useless, as it does nothing more than the original downloader from firefox except it has way more bugs.