Azure服务总线-唯一支持的IsolationLevel是'；IsolationLevel.Serializab

我正试图将消息推送到Azure服务总线上的主题，但当我这样做时，我会得到以下异常：

System.InvalidOperationException was unhandled by user code
  HResult=-2146233079
  Message=The only supported IsolationLevel is 'IsolationLevel.Serializable'.
  Source=Microsoft.ServiceBus
  StackTrace:
    Server stack trace: 
       at Microsoft.ServiceBus.Messaging.Sbmp.SbmpResourceManager.EnlistAsyncResult..ctor(SbmpResourceManager resourceManager, Transaction transaction, IRequestSessionChannel channel, SbmpMessageCreator messageCreator, Action`1 partitionInfoSetter, TimeSpan timeout, AsyncCallback callback, Object state)
       at Microsoft.ServiceBus.Messaging.Sbmp.SbmpResourceManager.BeginEnlist(Transaction transaction, IRequestSessionChannel channel, SbmpMessageCreator messageCreator, Action`1 partitionInfoSetter, TimeSpan timeout, AsyncCallback callback, Object state)
       at Microsoft.ServiceBus.Messaging.Sbmp.SbmpTransactionalAsyncResult`1.<>c__DisplayClass38.<GetAsyncSteps>b__32(TIteratorAsyncResult thisPtr, TimeSpan t, AsyncCallback c, Object s)
       at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.EnumerateSteps(CurrentThreadType state)
       at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.Start()
    Exception rethrown at [0]: 
       at Microsoft.ServiceBus.Common.AsyncResult.End[TAsyncResult](IAsyncResult result)
       at Microsoft.ServiceBus.Messaging.Sbmp.SbmpMessageSender.EndSendCommand(IAsyncResult result)
       at Microsoft.ServiceBus.Messaging.Sbmp.SbmpMessageSender.OnEndSend(IAsyncResult result)
       at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.EnumerateSteps(CurrentThreadType state)
    Exception rethrown at [1]: 
       at Microsoft.ServiceBus.Common.AsyncResult.End[TAsyncResult](IAsyncResult result)
       at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.RunSynchronously()
       at Microsoft.ServiceBus.Messaging.MessageSender.Send(TrackingContext trackingContext, IEnumerable`1 messages, TimeSpan timeout)
       at CryptoArb.Infrastructure.AzureStorage.ServiceBus.AzureServiceBusService.Send(String label, Object message)

服务总线代码如下：

public class AzureServiceBusService : IServiceBusService
{
    public ISettingsService SettingsService { get; set; }
    private NamespaceManager _namespaceManager;
    private string _topic;
    private TopicClient _topicClient;
    private TopicDescription _topicDescription;
    private string _connectionString;
    private SubscriptionClient _subscriptionClient;
    private string _subscriptionName = "AllMessages";
    public string Topic
    {
        get { return _topic; }
        set
        {
            _topic = value;
            _topicDescription = null;
            _topicClient = null;
        }
    }
    public SubscriptionClient SubscriptionClient
    {
        get
        {
            if (_subscriptionClient != null) return _subscriptionClient;
            if (!NamespaceManager.SubscriptionExists(TopicDescription.Path, _subscriptionName))
                NamespaceManager.CreateSubscription(TopicDescription.Path, _subscriptionName);
            _subscriptionClient = SubscriptionClient.CreateFromConnectionString(ConnectionString, TopicDescription.Path,
                _subscriptionName);
            return _subscriptionClient;
        }
    }

    internal string ConnectionString
    {
        get
        {
            if (String.IsNullOrWhiteSpace(_connectionString))
                _connectionString = SettingsService.ConnectionStrings[SettingsService.MainServiceBusConfigName].ConnectionString;
            return _connectionString;
        }
    }

    internal TopicClient TopicClient
    {
        get {
            return _topicClient ??
                   (_topicClient = TopicClient.CreateFromConnectionString(ConnectionString, TopicDescription.Path));
        }
    }
    internal TopicDescription TopicDescription
    {
        get
        {
            if (_topicDescription != null) return _topicDescription;
            if (!NamespaceManager.TopicExists(_topic))
                NamespaceManager.CreateTopic(_topic);
            _topicDescription = NamespaceManager.GetTopic(_topic);
            return _topicDescription;
        }
    }
    internal NamespaceManager NamespaceManager
    {
        get {
            if (_namespaceManager == null)
            {
                _namespaceManager = NamespaceManager.CreateFromConnectionString(ConnectionString);
                _namespaceManager.Settings.RetryPolicy = RetryExponential.Default;
            }
            return _namespaceManager;
        }
    }
    public AzureServiceBusService()
    {
        _topic = "default";
    }
    public AzureServiceBusService(string topic)
    {
        _topic = topic;
    }
    public void Send(string label, object message)
    {
        var brokeredMessage = new BrokeredMessage(message)
        {
            Label = label,
        };
        brokeredMessage.Properties["messageType"] = message.GetType().AssemblyQualifiedName;
        TopicClient.Send(brokeredMessage);
    }
    public ServiceBusMessage Receive()
    {
        var receivedMessage = SubscriptionClient.Receive();
        if (receivedMessage == null)
            return null;
        else
        {
            try
            {
                Type messageBodyType = null;
                if (receivedMessage.Properties.ContainsKey("messageType"))
                    messageBodyType = Type.GetType(receivedMessage.Properties["messageType"].ToString());
                if (messageBodyType == null)
                {
                    //Should never get here as a messagebodytype should
                    //always be set BEFORE putting the message on the queue
                    receivedMessage.DeadLetter();
                }
                var method = typeof(BrokeredMessage).GetMethod("GetBody", new Type[] { });
                var generic = method.MakeGenericMethod(messageBodyType);
                var messageBody = generic.Invoke(receivedMessage, null);
                var serviceBusMessage = new ServiceBusMessage()
                {
                    Body = messageBody,
                    MessageId = receivedMessage.MessageId
                };
                receivedMessage.Complete();
                return serviceBusMessage;
            }
            catch (Exception e)
            {
                receivedMessage.Abandon();
                return null;
            }
        }
    }
    public string SubscriptionName
    {
        get { return _subscriptionName; }
        set { _subscriptionName = value; }
    }
}

我已经确保到服务总线的连接字符串是有效的，并且在尝试使用主题和订阅之前，已经进行了检查以确保它们存在。

为什么我会得到例外？

using (var transaction = new TransactionScope(TransactionScopeOption.RequiresNew,
        new TransactionOptions {IsolationLevel = IsolationLevel.Serializable}))
{
    ...sending to the queue
    transaction.Complete();
}