Proposal for a new `lsetstat` extension

[stevenxxiu]

When porting SSHFS over to SFTP v6, I encountered an old issue of theirs, being that there was no support for [email protected]. #640038 - sshfs: cannot set timestamps of symbolic links - Debian Bug report logs.

SFTP v3 handles user and group via IDs and not strings. So OpenSSH's [email protected] won't really be applicable here.

What do you think about creating a new extension, that extends SSH_FXP_FSETSTAT so it sets the stat on the symlink?

[ewxrjk]

[email protected] takes an ATTRS argument, just like SSH_FXP_SETSTAT, so it would translate to later versions in a natural way.