Support for building Message objects from ArraySegments.

src/Microsoft.Azure.ServiceBus/Amqp/AmqpMessageConverter.cs

@@ -93,7 +93,9 @@ public static AmqpMessage BatchSBMessagesAsAmqpMessage(IEnumerable<SBMessage> sb
 
         public static AmqpMessage SBMessageToAmqpMessage(SBMessage sbMessage)
         {
-            var amqpMessage = sbMessage.Body == null ? AmqpMessage.Create() : AmqpMessage.Create(new Data { Value = new ArraySegment<byte>(sbMessage.Body) });
+            var messageData = sbMessage.BackingData;
+
+            var amqpMessage = messageData.Count <= 0 ? AmqpMessage.Create() : AmqpMessage.Create(new Data { Value = messageData });
 
             amqpMessage.Properties.MessageId = sbMessage.MessageId;
             amqpMessage.Properties.CorrelationId = sbMessage.CorrelationId;

src/Microsoft.Azure.ServiceBus/Extensions/MessageInterOpExtensions.cs

@@ -85,7 +85,9 @@ public static T GetBody<T>(this Message message, XmlObjectSerializer serializer
                 return (T)message.SystemProperties.BodyObject;
             }
 
-            if(message.Body == null || message.Body.Length == 0)
+            var messageData = message.BackingData;
+
+            if(messageData.Count == 0)
             {
                 return default;
             }
@@ -95,9 +97,9 @@ public static T GetBody<T>(this Message message, XmlObjectSerializer serializer
                 serializer = DataContractBinarySerializer<T>.Instance;
             }
 
-            using (var memoryStream = new MemoryStream(message.Body.Length))
+            using (var memoryStream = new MemoryStream(messageData.Count))
             {
-                memoryStream.Write(message.Body, 0, message.Body.Length);
+                memoryStream.Write(messageData.Array, messageData.Offset, messageData.Count);
                 memoryStream.Flush();
                 memoryStream.Position = 0;
                 return (T)serializer.ReadObject(memoryStream);