Prism - Using external examples?

I’m currently evaluating Prism for a project where we have an OAS 3 document that we would like to reference examples via URL and use those for mocked responses. Is this something Prism supports?

For example:

paths:
  /pets:
    get:
      summary: List all pets
      responses:
        '200':
          description: A paged array of pets
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pets"
              example:
                $ref: "http://localhost:8080/Pets.json"

I dropped a debug breakpoint in http/src/getHttpOperations.ts where Prism calls @stoplight/json-ref-resolver. Here the $ref is resolved as the string "object Object". My Pets.json is simply a JSON object on a local server.

Do I have something configured incorrectly? Or, is this something not supported?