some.kt

        fun post(url :String, json :JSONObject) : Promise<JSONObject> {
            return Promise.async(Callable<JSONObject> {
                val response: Response = this.postJson(url, json)
                if (!response.isSuccessful())
                    throw IOException(response.toString())
                val str = response.body().string()
                return JSONObject(str)
            })
        }