static async Task TestSQS(int numMsgs)
{
    Stopwatch stopWatch = new();

    using (AmazonSQSClient SQS = new("ignore", "ignore", new AmazonSQSConfig { ServiceURL = "http://localhost:4566" }))
    {
        // Create a queue.
        CreateQueueResponse createQueueResp = await SQS.CreateQueueAsync($"testQueue_{Guid.NewGuid()}");
        string msgText = new('x', 100);
        ReceiveMessageRequest receiveMessageReq = new(createQueueResp.QueueUrl)
        {
            WaitTimeSeconds = 5,
            MaxNumberOfMessages = 10
        };

        // Send messages
        Console.WriteLine($"Sending {numMsgs} messages...");
        Task[] sentMsgs = new Task[numMsgs];
        stopWatch.Restart();
        for (int i = 0; i < numMsgs; i++)
        {
            sentMsgs[i] = SQS.SendMessageAsync(createQueueResp.QueueUrl, msgText);
        }
        await Task.WhenAll(sentMsgs);
        stopWatch.Stop();
        Console.WriteLine($"Num. messages={numMsgs}  Sending time={stopWatch.ElapsedMilliseconds:F0} ms");

        // Process (receive/delete) messages
        Console.WriteLine($"Processing {numMsgs} messages...");
        Stopwatch stopWatchRcv = new();
        Stopwatch stopWatchDel = new();
        int msgCount = 0;
        stopWatch.Restart();
        while (msgCount < numMsgs)
        {
            stopWatchRcv.Start();
            receiveMessageResp = await SQS.ReceiveMessageAsync(receiveMessageReq);
            stopWatchRcv.Stop();
            stopWatchDel.Start();
            foreach (Amazon.SQS.Model.Message msg in receiveMessageResp.Messages)
            {
                await SQS.DeleteMessageAsync(createQueueResp.QueueUrl, msg.ReceiptHandle);
            }
            stopWatchDel.Stop();
            msgCount += receiveMessageResp.Messages.Count;
        }
        stopWatch.Stop();
        Console.WriteLine($"Num. messages={msgCount}  Processing time={stopWatch.ElapsedMilliseconds:F0} ms  (Receiving={stopWatchRcv.ElapsedMilliseconds:F0} ms Deleting={stopWatchDel.ElapsedMilliseconds:F0} ms)");

        await SQS.DeleteQueueAsync(createQueueResp.QueueUrl);
    }
}