（Bot 框架 c#）在瀑布对话框中发送输入指示符

Question

我想模拟在瀑布对话框中输入。我已经尝试了下面的代码，但它不起作用（有延迟，毕竟是文本）。怎么做（如果可能的话）？

private async Task<DialogTurnResult> ConfidentialityStepAsync(WaterfallStepContext stepContext, CancellationToken cancellationToken)
        {
            await stepContext.Context.SendActivityAsync(MessageFactory.Text("Confidentiality is very important for me"), cancellationToken);
            
            await stepContext.Context.SendActivityAsync(MessageFactory.Text("All your data are completely safe"), cancellationToken);

            var confidentiality = stepContext.Context.Activity.CreateReply();
            var url = new HeroCard
            {
                Text = "Terms of use",
                Buttons = new List<CardAction> { new CardAction(ActionTypes.OpenUrl, "More informations", value: "") },
            };

            confidentiality.Attachments = new List<Attachment>() { url.ToAttachment() };

            await stepContext.Context.SendActivityAsync(confidentiality, cancellationToken);
            return await stepContext.NextAsync(cancellationToken: cancellationToken);
        }

private async Task<DialogTurnResult> TermsStepAsync(WaterfallStepContext stepContext, CancellationToken cancellationToken)
        {
            await stepContext.Context.SendActivitiesAsync(
                new Activity[] {
                    new Activity { Type = ActivityTypes.Typing },
                    new Activity { Type = "delay", Value= 2000 },
                    MessageFactory.Text("XXXXXXXXx"),
                 }, cancellationToken);

            return await stepContext.NextAsync(cancellationToken: cancellationToken);
        }