ZFS delegation- zfs send| zfs recv fails for not being able to unmount dataset as regular user

Hi there,

How do I get around the the issue of normal user being unable to unmount
the dataset ...

# zfs send -R -v send-test/original@to-copy | zfs recv -F -d -v -s
send-test-copy
full send of send-test/original@to-copy estimated size is 51.1K
total estimated size is 51.1K
cannot unmount '/send-test-copy/original': permission denied
warning: cannot send 'send-test/original@to-copy': Broken pipe

... so that the transfer would succeed?

I am testing ZFS delegation on FreeBSD 13, with ...

# zpool list | grep send-test
send-test         48M   520K  47.5M        -         -    10%     1%
1.00x    ONLINE  -
send-test-copy    48M   540K  47.5M        -         -     9%     1%
1.00x    ONLINE  -

# zfs list  -tall | grep send-test
send-test                     520K  23.5M       96K  /send-test
send-test-copy                540K  23.5M       96K  /send-test-copy
send-test-copy/original        96K  23.5M       96K  /send-test-copy/original
send-test/original            112K  23.5M      112K  /send-test/original
send-test/original@to-copy      0B      -      112K  -

# zfs allow send-test-copy
---- Permissions on send-test-copy -----------------------------------
Local+Descendent permissions:
        user parv
create,destroy,diff,hold,mount,promote,receive,release,send,snapshot

# ll /send-test-copy
total 10
drwxr-xr-x   3 parv  parv   uarch  3 20210805.1741 ./
drwxr-xr-x  25 root  wheel  uarch 31 20210805.1715 ../
drwxr-xr-x   2 parv  parv   uarch  2 20210805.1741 original/

- parv