NullTransport for WCF

using System;
using System.Xml;
using System.Collections.Generic;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Channels;
using System.ServiceModel.Dispatcher;
using System.Reflection;

using System.Text;

namespace Contract
{
    public class CreateWorkflowMessageInspector : IDispatchMessageInspector
    {
        DispatchOperation _dispatch = null;
        XmlQualifiedName _durableDispatchContextName = null;

        public CreateWorkflowMessageInspector(DispatchOperation dispatch)
        {
            _dispatch = dispatch;
            _durableDispatchContextName = new XmlQualifiedName("InstanceId", "http://schemas.microsoft.com/ws/2006/05/context");
        }

        #region IDispatchMessageInspector Members
        public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
        {
            string strInstanceId = null;
            ContextMessageProperty cmp = null;

            if (_dispatch.Action == request.Headers.Action && 
                ContextMessageProperty.TryGet(request, out cmp) &&
                cmp.TryGetValue(_durableDispatchContextName, out strInstanceId) && 
                instanceContext.Extensions.Count == 1)
            {
                PropertyInfo pi = _dispatch.Invoker.GetType().GetProperty("CanCreateInstance"); 
                if (pi != null)
                {
                    // get property from WorkflowOperationInvoker
                    bool canCreateInstance = (bool)pi.GetValue(_dispatch.Invoker, null);
                    if (canCreateInstance)
                    {
                        // update WorkflowDurableInstance field
                        IExtension<InstanceContext>[] arr = new IExtension<InstanceContext>[1];
                        instanceContext.Extensions.CopyTo(arr, 0);
                        FieldInfo fi = arr[0].GetType().GetField("shouldCreateNew", BindingFlags.Instance | BindingFlags.NonPublic);
                        if (fi != null)
                        {
                          fi.SetValue(arr[0], true);
                          request.Properties["newDurableInstanceIdProperty"] = new Guid(strInstanceId);
                          return strInstanceId;
                        }
                    }
                }            
            }
            return null;
        }

        public void BeforeSendReply(ref Message reply, object correlationState) {}
        #endregion
    }

    [AttributeUsage(AttributeTargets.Method)]
    public class CreateWorkflowAttribute : Attribute, IOperationBehavior
    {
        public void AddBindingParameters(OperationDescription description, BindingParameterCollection parameters){}
        public void ApplyClientBehavior(OperationDescription description, ClientOperation proxy) {}
        public void Validate(OperationDescription description) { }
        public void ApplyDispatchBehavior(OperationDescription description, DispatchOperation dispatch)
        {
            if (description.Behaviors.Contains(typeof(CreateWorkflowAttribute)))
            {
                dispatch.Parent.MessageInspectors.Add(new CreateWorkflowMessageInspector(dispatch));
            }
        }   
    }
}