add zfs send -w

[lamixer]

I think there is some reason you don't want to do this, because I think I have suggested it before. I forked this repo and made a pull request in my fork which adds the -w flag to zfs-send by using the --encrypted option in a pve-zsync command. It is here: lamixer#1

It has been working for me.

[ThomasLamprecht]

We only use github as read-only mirror, please see our developer docs for how to contribute patches:
https://pve.proxmox.com/wiki/Developer_Documentation

FWIW, I think calling the setting encrypted is not ideal, as the -w option does not encrypt things at all, so users could be misguided by this option name.
As -w is the short-option for the --raw long option, I'd probably also just name it raw or possible more verbose, like send-encrypted-as-raw, as this is what it does.

[lamixer]

I suppose that would be more accurate. But I think the only reason to use RAW currently is to send a filesystem keeping encryption intact. In fact it is the only way for incremental zfs send of encrypted filesystems to work. Some explanation would be helpful to the user.

Since I'm not really submitting original code here, I won't go through the process you linked. But I encourage you to implement some flag for -w into your very handy pve-zsync. Thanks.