/**
         * Fetch discount from server.
         */
        private async System.Threading.Tasks.Task FetchDiscount()
        {
            mPriceTextView.SetText(LOADING_PHRASE_CONFIG_KEY, null);

            long cacheExpiration = 3600;             // 1 hour in seconds.

            try
            {
                await mFirebaseRemoteConfig.FetchAsync(cacheExpiration);

                Toast.MakeText(this, "Fetch Succeeded", ToastLength.Long).Show();

                // Once the config is successfully fetched it must be activated before newly fetched
                // values are returned.
                mFirebaseRemoteConfig.Activate().Wait();
            }
            catch
            {
                Toast.MakeText(this, "Fetch Failed", ToastLength.Long).Show();
            }

            DisplayPrice();
        }