Persistence of libtorrent session state

[veloman-yunkan]

libtorrent session must be persisted so that incomplete downloads can be resumed after restarting kiwix-desktop.

[ayushman1210]

Hi @veloman-yunkan,
Are you currently working on this issue? If not, I would be happy to take it up and submit a PR.
Please let me know if I can proceed.
Thank you!

[veloman-yunkan]

@ayushman1210 Thank you for your interest in contributing to Kiwix projects but please look for another ticket. This one is on my plate :)