Custom Retrofit converter for wrapped responses

Converter.kt

class CustomConverterFactory(gson: Gson) : Converter.Factory() {

     private val gsonConverterFactory: GsonConverterFactory = GsonConverterFactory.create(gson)

    override fun responseBodyConverter(type: Type, annotations: Array<Annotation>, retrofit: Retrofit): Converter<ResponseBody, *>? {
        val wrappedType = object : ParameterizedType {
            override fun getActualTypeArguments(): Array<Type> = arrayOf(type)
            override fun getOwnerType(): Type? = null
            override fun getRawType(): Type = Data::class.java
        }
        val gsonConverter: Converter<ResponseBody, *>? = gsonConverterFactory.responseBodyConverter(wrappedType, annotations, retrofit)
        return ResponseBodyConverter(gsonConverter as Converter<ResponseBody, Data<Any>>)
    }

    override fun requestBodyConverter(type: Type?, parameterAnnotations: Array<Annotation>, 
                                      methodAnnotations: Array<Annotation>, retrofit: Retrofit): Converter<*, RequestBody>? {
        return gsonConverterFactory.requestBodyConverter(type!!, parameterAnnotations, methodAnnotations, retrofit)
    }
}


class ResponseBodyConverter<T>(private val converter: Converter<ResponseBody, Data<T>>) : Converter<ResponseBody, T> {

    @Throws(IOException::class)
    override fun convert(responseBody: ResponseBody): T {
        val response = converter.convert(responseBody)
        return if (response.statusCode == 0) response.data? else throw ApiException(response.statusCode, response.message?)
    }
}