make it clear that the user needs to deal with NServiceBus messages in addition to native messages

Snippets/ASQ/ASQN_13/CustomEnvelopeUnwrapper.cs

@@ -1,6 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Text.Json;
+using System.Buffers.Text;
 using NServiceBus;
 using NServiceBus.Azure.Transports.WindowsAzureStorageQueues;
 
@@ -15,23 +13,18 @@ class CustomEnvelopeUnwrapper
         {
             MessageUnwrapper = queueMessage =>
             {
-                var messageText = Convert.FromBase64String(queueMessage.MessageText);
-
-                //try deserialize to a NServiceBus envelope first
-                var wrapper = JsonSerializer.Deserialize<MessageWrapper>(messageText);
-
-                if (wrapper?.Id != null)
-                {
-                    //this was a envelope message
-                    return wrapper;
-                }
-
+                //This sample expects the native message to be serialized only,
+                // conforming to the specified endpoint serializer.
+                //NServiceBus messages will always be Base64 encoded, so any messages
+                // of this type can be forwarded to the framework by returning null.
+                return Base64.IsValid(queueMessage.MessageText)
+                ? null
                 //this was a native message just return the body as is with no headers
-                return new MessageWrapper
+                : new MessageWrapper 
                 {
                     Id = queueMessage.MessageId,
-                    Headers = new Dictionary<string, string>(),
-                    Body = messageText
+                    Headers = [],
+                    Body = queueMessage.Body.ToArray()
                 };
             }
         };

samples/azure/native-integration-asq/ASQN_13/Receiver/Program.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Buffers.Text;
 using System.Collections.Generic;
 
 using NServiceBus;
@@ -18,15 +19,18 @@
 
 #region Native-message-mapping
 
-transport.MessageUnwrapper = message => new MessageWrapper
-{
-    Id = message.MessageId,
-    Body = message.Body.ToArray(),
-    Headers = new Dictionary<string, string>
-            {
-                { Headers.EnclosedMessageTypes, typeof(NativeMessage).FullName }
-            }
-};
+transport.MessageUnwrapper = message =>
+    Base64.IsValid(message.MessageText)
+    ? null // not a raw native message - allow the framework to deal with it
+    : new MessageWrapper
+    {
+        Id = message.MessageId,
+        Body = message.Body.ToArray(),
+        Headers = new Dictionary<string, string>
+        {
+            { Headers.EnclosedMessageTypes, typeof(NativeMessage).FullName }
+        }
+    };
 
 #endregion
 

transports/azure-storage-queues/native-integration_sending_asqn_[11,).partial.md

@@ -0,0 +1,15 @@
+### Custom envelope unwrapper
+
+Azure Storage Queues lacks native header support. NServiceBus solves this by wrapping headers and message body in a custom envelope structure. This envelope is serialized using the configured [serializer](/nservicebus/serialization) for the endpoint before being sent.
+
+Creating this envelope can cause unnecessary complexity if headers are not needed, as is the case in native integration scenarios. For this reason, NServiceBus.Transport.AzureStorageQueues 9.0 and above support configuring a custom envelope unwrapper. 
+
+> [!WARNING]
+> In this scenario, NServiceBus may place messages in your queue in addition to the native messages that are expected, for example if a message results in a [delayed retry](delayed-delivery.md). Any custom envelope unwrapper must verify if the incoming message is capable of being deserialized as a native message, and the resulting body must be serialized according to the configured endpoint serializer. If either of these conditions cannot be met then `MessageUnwrapper` should return `null` to allow the default unwrapper to handle the message.
+
+The snippet below shows custom unwrapping logic that enables both NServiceBus formatted and plain serialized messages to be consumed.
+
+snippet: CustomEnvelopeUnwrapper
+
+> [!NOTE]
+> This feature is currently NOT compatible with ServiceControl. A [ServiceControl transport adapter](/servicecontrol/transport-adapter.md) is required to leverage both.

transports/azure-storage-queues/native-integration_sending_asqn_[9,10].partial.md

@@ -0,0 +1,15 @@
+### Custom envelope unwrapper
+
+Azure Storage Queues lacks native header support. NServiceBus solves this by wrapping headers and message body in a custom envelope structure. This envelope is serialized using the configured [serializer](/nservicebus/serialization) for the endpoint before being sent.
+
+Creating this envelope can cause unnecessary complexity if headers are not needed, as is the case in native integration scenarios. For this reason, NServiceBus.Transport.AzureStorageQueues 9.0 and above support configuring a custom envelope unwrapper. 
+
+> [!WARNING]
+> In this scenario, NServiceBus may place messages in your queue in addition to the native messages that are expected, for example if a message results in a [delayed retry](delayed-delivery.md). Any custom envelope unwrapper must verify if the incoming message is capable of being deserialized as a native message, and the resulting body must be serialized according to the configured endpoint serializer.
+
+The snippet below shows custom unwrapping logic that enables both NServiceBus formatted and plain serialized messages to be consumed.
+
+snippet: CustomEnvelopeUnwrapper
+
+> [!NOTE]
+> This feature is currently NOT compatible with ServiceControl. A [ServiceControl transport adapter](/servicecontrol/transport-adapter.md) is required to leverage both.