Supergroups downloading starts over after interrupts

[bodqhrohro]

If an interrupt occurred during fetching the messages of a supergroup (network outages, shutdown and so on), the next time telegram_backup proceeds to this supergroup it starts fetching it over, not from the point it reached right before the interrupt. This is very inconvenient as some supergroups have hundreds of thousands of messages and it's hard to fetch all of them in one run.

[bodqhrohro]

Huh, looks like this is a false call. I noticed that in a supergroup that already had been completely fetched, only a bit of new messages were synced on new iteration:

...200...400...600...800...1000...1156 done.

So probably the messages fetched before an interruption are not re-fetched as well.

If the progress counter is misleading, it should start not always from zero but from the number of already fetched messages. Or, as an another option, the number of already fetched messages should be printed separately before the sync starts.