`zfs send` immediately stops with "Assertion failed: (progress)"
I migrated this server a few times already on new hardware over the
years, by using `zfs send`.
Even right now I'm using `zrepl` to periodically have a remote copy to a
distant site (for disaster recovery).
But trying to migrate on a new server in the same server farm recently
I'm seeing this error:
$ sudo zfs send -Rv z@recentSnapshot >/dev/null
Assertion failed: (progress), file
This is happening in a freshly updated FreeBSD 12.2-RELEASE-p2.
I don't know how to reproduce it (or debug it) and the server is serving
production data, so I can only do non-intrusive tests.
I guess it has something to do with clones, given the comments at line
1480 and line 1492 so maybe I can print something with `zdb`?
Any idea how to debug (and solve)?