curl --request POST \
  --url https://management.api.smartcar.com/v3/subscriptions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "data": {
    "attributes": {
      "webhookId": "webhook_12345",
      "userId": "user_12345",
      "vehicleId": "vehicle_67890"
    }
  }
}
'

{
  "meta": {
    "message": "subscription creation in progress"
  }
}