Option to push update notification based on time and not STEP_UPDATE pct.

Notifications are sent at 5% increments or if 100% download is reached. For small files this can result in a flood of notification events. It would be really useful to be able to either specify the increment percentage or, even better, as a duration. For example, send a notification at per-second intervals. This would provide consistent update notifications regardless of file size.

Thanks.

Start by locating the code that emits notifications at 5% increments or at 100% completion, using STEP_UPDATE as the search term. Review how download progress is handled and define whether the option should accept a percentage increment, a duration, or both; done means small files no longer produce a notification flood while progress updates remain consistent.

Written by the indexing model from the issue text.