Asset: clone() doesn't clone extra_fields

[m-mohr]

If you do asset.clone() you get a shallow copy, but as extra_field is explicitily a member of the class, I'd expect that it at least also get cloned.

The following code adds abc to both asset and mask, which is somewhat unexpected:

fields = {}
asset = Asset(
    href=href,
    extra_fields=fields,
)
mask = asset.clone()
mask.extra_fields["abc"] = True

[m-mohr]

Thank you.