class NullOnEmptyConverterFactory : Converter.Factory() {
    override fun responseBodyConverter(type: Type?, annotations: Array<Annotation>?, retrofit: Retrofit?): Converter<ResponseBody, *>? {
        val delegate = retrofit!!.nextResponseBodyConverter<Any>(this, type!!, annotations!!)
        return Converter<ResponseBody, Any> {
            if (it.contentLength() == 0L) return@Converter ResponseSuccess(true, "", null)
            delegate.convert(it)
        }
    }

}