Bug 448896

SUMMARY
When we try to unmount a USB device (via Disks & Devices applet) immediately after copying large amount of data,
the system takes a while to unmount the device due to the file copy in progress in background (see bug 281270).
When the device is finally unmounted and can be safely removed, Plasma just opens and closes the Disks & Devices applet in system tray. However, it's not clear what this behavior means. I think that a notification would be a better and clearer way to tell the user that the device can be safely unplugged.


STEPS TO REPRODUCE
1. copy large amount of data to a USB device
2. when Plasma notification showing data transfer progress to disappear, try to unmount the USB device immediately via 'Safely remove' button of Disks & Devices applet in system tray (the applet says 'Removing...'). A few minutes later (the amount of time depends on the amount of data copied), Disks & Applets opens and closes and it's not clear what this behavior means.
3. 

OBSERVED RESULT
we do not receive a clear feedback when unmounting is completed and the usb device can be safely unplugged

EXPECTED RESULT
a notification telling us when the usb device can be safely unplugged

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.23.90
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
Graphics Platform: Wayland