Ensure that null is sent through on DelaySeconds

src/OpenMessage.AWS.SQS/SqsDispatcher.cs

@@ -65,11 +65,14 @@ public override async Task DispatchAsync(Message<T> message, CancellationToken c
             var request = new SendMessageRequest
             {
                 MessageAttributes = GetMessageProperties(message),
-                DelaySeconds = DelaySeconds(message),
                 MessageBody = msg,
                 QueueUrl = _queueUrl
             };
 
+            var delay = DelaySeconds(message);
+            if (delay.HasValue)
+                request.DelaySeconds = delay.Value;
+
 #if NETCOREAPP3_1
             var stopwatch = OpenMessageEventSource.Instance.ProcessMessageDispatchStart();
 #endif
@@ -89,14 +92,14 @@ public override async Task DispatchAsync(Message<T> message, CancellationToken c
             }
         }
 
-        private static int DelaySeconds(Message<T> message)
+        private static int? DelaySeconds(Message<T> message)
         {
             if (message is ISupportSendDelay delay && delay.SendDelay > TimeSpan.Zero)
             {
                 return Math.Min(MaximumSqsDelaySeconds, (int) delay.SendDelay.TotalSeconds);
             }
 
-            return 0;
+            return null;
         }
 
         private Dictionary<string, MessageAttributeValue> GetMessageProperties(Message<T> message)

src/OpenMessage.AWS.SQS/SqsDispatcherService.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Channels;
@@ -138,7 +138,7 @@ private async Task ProcessMessages(List<SendSqsMessageCommand> messages)
 
                 var response = await client.SendMessageBatchAsync(request);
 
-                // TODO :: we should be able to complete certain messages here
+                // TODO :: Complete elements in the batch that we can
                 if (response.Failed.Count > 0)
                     Throw.Exception("One or more messages failed to send");