Hi

I'm trying to figure out how to put links on objects to actions with this extension.
With DRF without any other extensions I'm able to use HyperlinkedIdentityField in the serializer to add the link to a view as can be seen in the following code and screenshot of output json.

from rest_framework.viewsets import ModelViewSet
from rest_framework.relations import HyperlinkedIdentityField
from rest_framework.serializers import HyperlinkedModelSerializer

class ActivityListSet(ModelViewSet):
    queryset = Activity.objects.all()
    serializer_class = ActivitySerializer

    @action(detail=True)
    def geojson(self, request, pk=None):
        return Response({"a": "test"})

class ActivitySerializer(HyperlinkedModelSerializer):

    geo_json = HyperlinkedIdentityField(
        view_name="activity-geojson"
    )

    class Meta:
        model = Activity
        fields = [
            "self",
            "status",
            "error",
            "started_at",
            "completed_at",
            "geo_json"
        ]

However once switching over to use the DRF Json API equivalent (HyperlinkedIndentityField does not seem to exist) I'm getting the following error:
type object 'Activity' has no attribute 'geo_json'

I've searched through the issues in the project as well as the documentation, but I'm unable to find out why this does not work with this extension. DRF also has an example with a similar use case as mine, so it seems like I'm using HyperlinkedIdentityField as intended

Would greatly appreciate if anyone can help me figure out how to solve this issue