Unset field with `import --set`

[dschrempf]

When using modify one can unset a field using field!. It is not possible to do so using the set_fields importer option nor the --set command line option.

error: supplied argument `subcollection!' is not of the form `key=value'

How can I unset a field during import using the the configuration or command line option? (I don't want to set it to the empty string).

[sampsyo]

This is not currently possible, AFAIK, so I have marked it as a feature request.