Handle failed port forwarding

[Aldaviva]

piactl.exe get portforward
Failed

Seems to be happening very frequently these days, like one failure every day or two, using the same VPN server that previously went for months with no port forwarding failures.

[Aldaviva]

I don't think there is a clean way to fix this with the qBittorrent API 5.0. Before reconnecting the VPN, all torrents should be paused, but this functionality is only available in the qBittorrent QT UI for some reason, but not the web UI or API. It was added in 5.0. Without this feature, torrents would continue to run while the VPN is disconnected. I don't fully trust the Options > Advanced > Network Interface binding, and not all users may configure that. The API only allows you to pause or resume all torrents, which is not isomorphic because torrents that were already paused before pausing all will be resumed, instead of left paused like Pause Session correctly and helpfully does. This deficiency in the API was noted 6 months ago in the umbrella issue qbittorrent/qBittorrent # 9796, but does not have a bug attached to this specific item.

Other ideas include

1. exiting qBittorrent (very destructive, can take a long time to resume as it scans all file sizes, can lose data if you were in the middle of something like adding a new torrent)
2. setting transfer speed to zero, waiting, and then restoring the old speed limits once it's done (may still allow connections to trackers, may take a long or indeterminate amount of time for all traffic to stop)
3. add a Windows Firewall rule that blocks all traffic to qBittorrent (this program used to do this, but I'm not sure it correctly closed active connections, only new ones, so this doesn't stop existing traffic like we need)
4. try to automate qBittorrent QT UI somehow (this program runs as a service and does not have UI access to the windows of the user running qBittorrent, and even if we did it's a UI automation nightmare with tray icons and everything)
5. send keyboard shortcuts to qBittorrent window (Ctrl+Shift+P to pause, Ctrl+Shift+S to resume), and you can tell if the session is paused if the window title starts with [PAUSED] ), which probably has the same drawbacks as 4 due to user accounts and services