Test.cs

var updateReceiver = new QueuedUpdateReceiver(Bot);

updateReceiver.StartReceiving(new[] { UpdateType.Message }, errorHandler: HandleErrorAsync);

_ = Task.Run(async () => {
    while (true)
    {
        Console.WriteLine(
            DateTime.Now.Second.ToString().PadLeft(2, '0') +
            " Pending: " + updateReceiver.PendingUpdates +
            " Status: " + (updateReceiver.IsReceiving ? "" : "NOT ") + "receiving");
        await Task.Delay(100);
    }
});

await foreach (Update update in updateReceiver.YieldUpdatesAsync())
{
    if (update.Message is Message message && message.Text is string text)
    {
        await Bot.SendTextMessageAsync(message.Chat, $"Pending: {updateReceiver.PendingUpdates} updates\nEcho:\n{text}");

        if (text.StartsWith("wait") && text.Length > 5 && int.TryParse(text.AsSpan(5), out int waitMs) && waitMs > 0)
            await Task.Delay(waitMs);

        if (text == "break")
            break;

        if (text == "stop")
            updateReceiver.StopReceiving();
    }
}

Console.WriteLine("Exited the loop");
Console.ReadLine();