curl --request GET \
  --url https://sandbox.nmbr.co/services/payroll/async_tasks/{async_task} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<id>",
  "object": "async_task",
  "data": {
    "type": "form_generation",
    "status": "processing",
    "completed_at": null,
    "results": [],
    "created_at": "2026-01-01T00:00:00.000000Z",
    "updated_at": "2026-01-01T00:00:00.000000Z"
  },
  "links": {
    "self": "/async_tasks/<id>"
  }
}