AsyncTask and Retrofit

RetrofitAndAsyncTask.kt

private class PetTask(val petList: ArrayList<Pet>, val petManager: PetManager): AsyncTask<Void, Void, Response<JsonResponse>>() {
        override fun doInBackground(vararg params: Void?): Response<JsonResponse> {
            return petManager.getPetList("78701").execute()
        }

        override fun onPostExecute(result: Response<JsonResponse>?) {
            result?.body()?.petFinder?.pets?.pet?.let {
                petList.addAll(it)
            }
        }
    }

interface PetManager {
    @GET("pet.find")
    fun getPetList(@Query("location") location: String): Call<JsonResponse>
}

class PetManagerImpl: PetManager {
    private val retrofitInstance = RetrofitFactory.retrofit().create(PetManager::class.java)

    override fun getPetList(location: String): Call<JsonResponse> {
        return retrofitInstance.getPetList(location)
    }
}