private async Task ResetRichMenuAsync(string replyToken, string userId)
{
var richMenuId = await Client.GetRichMenuOfUser(userId);
await Client.UnlinkRichMenuFromUser(userId);
// This is for testing.
// Generally, in my opinion, you should reuse rich menus.
await Client.DeleteRichMenu(richMenuId);
await Client.ReplyTextAsync(replyToken, $"Deleted your rich menu.\nrichMenuId: {richMenuId}");
}