No BOM for serialized output

src/NServiceBus.Newtonsoft.Json/JsonMessageSerializer.cs

@@ -16,6 +16,7 @@ class JsonMessageSerializer : IMessageSerializer
         Func<Stream, JsonReader> readerCreator;
         Func<Stream, JsonWriter> writerCreator;
         NewtonSerializer jsonSerializer;
+        static readonly Encoding utf8NoBOM = new UTF8Encoding(false);
 
         public JsonMessageSerializer(
             IMessageMapper messageMapper,
@@ -33,7 +34,7 @@ public JsonMessageSerializer(
 
             this.writerCreator = writerCreator ?? (stream =>
             {
-                var streamWriter = new StreamWriter(stream, Encoding.UTF8);
+                var streamWriter = new StreamWriter(stream, utf8NoBOM);
                 return new JsonTextWriter(streamWriter)
                 {
                     Formatting = Formatting.None

src/Tests/No_UTF8_BOM.cs

@@ -0,0 +1,37 @@
+using System.IO;
+using System.Text;
+using NServiceBus.MessageInterfaces.MessageMapper.Reflection;
+using NServiceBus.Newtonsoft.Json;
+using NUnit.Framework;
+
+[TestFixture]
+public class No_UTF8_BOM
+{
+
+    [Test]
+    public void Run()
+    {
+        var messageMapper = new MessageMapper();
+        var serializer = new JsonMessageSerializer(messageMapper, null, null, null, null);
+        var message = new SimpleMessage();
+        using (var stream = new MemoryStream())
+        {
+            serializer.Serialize(message, stream);
+
+            stream.Position = 0;
+
+            var result = stream.ToArray();
+            var utf8bom = new UTF8Encoding(true).GetPreamble();
+
+            for (var i = 0; i < utf8bom.Length; i++)
+            {
+                Assert.AreNotEqual(utf8bom[i], result[i]);
+            }
+        }
+    }
+    public class SimpleMessage
+    {
+        public string SomeProperty { get; set; }
+    }
+
+}

src/Tests/With_UTF8_BOM.cs

@@ -0,0 +1,33 @@
+using System.IO;
+using System.Text;
+using NServiceBus.MessageInterfaces.MessageMapper.Reflection;
+using NServiceBus.Newtonsoft.Json;
+using NUnit.Framework;
+
+[TestFixture]
+public class With_UTF8_BOM
+{
+
+    [Test]
+    public void Run()
+    {
+        var messageMapper = new MessageMapper();
+        var serializer = new JsonMessageSerializer(messageMapper, null, null, null, null);
+
+        var serialized = new UTF8Encoding(true).GetBytes($"{{\"{nameof(SimpleMessage.SomeProperty)}\":\"John\"}}");
+
+        using (var stream = new MemoryStream(serialized))
+        {
+            stream.Position = 0;
+
+            var result = (SimpleMessage)serializer.Deserialize(stream, new[] { typeof(SimpleMessage) })[0];
+
+            Assert.AreEqual("John", result.SomeProperty);
+        }
+    }
+    public class SimpleMessage
+    {
+        public string SomeProperty { get; set; }
+    }
+
+}