Serialize state of archiver

[stefanomasini]

I'm trying to write a ZIP file in chunks, by separate independent processes running at different times (but in the right serialized order). Ideally each process should append one single file, and the last process, after writing the last file, also finalizes the archive.

It would be great if it was possible to serialize the state of the archiver, so that each process can pick up where the previous one left.

I quickly read the code and it looks like there's really just a handful of internal variables that would need to be serialized, and probably JSON should suffice.

Would that be possible or is there some show stopper I'm not currently seeing?
If possible, what would be the internal variables to take care of? That would give me a head start for a PR.

Thanks for the great library! A work of art.