fix for Value beingserialized

src/NServiceBus.AcceptanceTests/DataBus/When_sending_databus_properties_with_systemjsonserializer.cs

@@ -1,10 +1,12 @@
 namespace NServiceBus.AcceptanceTests.DataBus
 {
+    using System;
     using System.IO;
     using System.Threading.Tasks;
     using AcceptanceTesting;
     using AcceptanceTesting.Customization;
     using EndpointTemplates;
+    using NServiceBus.MessageMutator;
     using NUnit.Framework;
 
     public class When_sending_databus_properties_with_systemjsonserializer : NServiceBusAcceptanceTest
@@ -56,6 +58,7 @@ public Receiver()
                     var basePath = Path.Combine(TestContext.CurrentContext.TestDirectory, "databus", "sender");
                     builder.UseDataBus<FileShareDataBus, SystemJsonDataBusSerializer>().BasePath(basePath);
                     builder.UseSerialization<SystemJsonSerializer>();
+                    builder.RegisterMessageMutator(new Mutator());
                 });
             }
 
@@ -77,6 +80,18 @@ public Task Handle(MyMessageWithLargePayload messageWithLargePayload, IMessageHa
             }
         }
 
+        public class Mutator : IMutateIncomingTransportMessages
+        {
+            public Task MutateIncoming(MutateIncomingTransportMessageContext context)
+            {
+                if (context.Body.Length > PayloadSize)
+                {
+                    throw new Exception("The message body is too large, which means the DataBus was not used to transfer the payload.");
+                }
+                return Task.CompletedTask;
+            }
+        }
+
         public class MyMessageWithLargePayload : ICommand
         {
             public DataBusProperty<byte[]> Payload { get; set; }

src/NServiceBus.Core/DataBus/DataBusProperty.cs

@@ -50,6 +50,7 @@ protected DataBusProperty(SerializationInfo info, StreamingContext context)
         /// <summary>
         /// The value.
         /// </summary>
+        [JsonIgnore]
         public T Value => value;
 
         /// <summary>