override fun componentDidMount() {
        window.fetch("/api/hello")
                .then { response ->
                    response.text().then { text ->
                        setState {
                            message = JSON.parse<HelloResponse>(text).message
                        }
                    }
                     .catch {
                         setState {
                                    message = "error parsing json"
                         }
                     }
                }
                .catch {
                    setState {
                        message = "error fetch from Hello Service"
                    }
                }
    }