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diff --git a/AVStream/avscamera/sys/WorkItem.cpp b/AVStream/avscamera/sys/WorkItem.cpp
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+++ b/AVStream/avscamera/sys/WorkItem.cpp
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+/**************************************************************************
+
+    A/V Stream Camera Sample
+
+    Copyright (c) 2014, Microsoft Corporation.
+
+    File:
+
+        workitem.cpp
+
+    Abstract:
+
+        This module contains an implementation for KWorkItem.
+
+        A KWorkItem inherits from CRef and is reference counted.  The object 
+        cannot be destroyed until all references are released.  This includes
+        the reference held when the workitem is in flight.  This allows you 
+        to store the workitem in an object that has a lifecycle shorter than
+        the parent device object.
+
+    History:
+
+        created 5/30/2014
+
+**************************************************************************/
+
+#include "Common.h"
+
+KWorkItem::
+KWorkItem(
+    _In_    PDEVICE_OBJECT          DeviceObj,
+    _In_    PIO_WORKITEM_ROUTINE    Callback,
+    _In_    PVOID                   Context,
+    _In_    WORK_QUEUE_TYPE         QueueType
+)
+    : m_Callback( Callback )
+    , m_Context ( Context  )
+    , m_QueueType( QueueType )
+/*++
+
+Routine Description:
+
+    Constructor.  
+    
+    Sets up callback handler for the workitem and performs initialization.
+
+Arguments:
+
+    None.
+
+Return Value:
+
+    None.
+
+--*/
+{
+    m_WorkItem = IoAllocateWorkItem( DeviceObj );
+}
+
+
+KWorkItem::
+~KWorkItem()
+/*++
+
+Routine Description:
+
+    Destructor.  
+    
+    Blocks until all references are released, then frees the workitem.
+
+Arguments:
+
+    None.
+
+Return Value:
+
+    None.
+
+--*/
+{
+    //  Make sure the work item has been run down.
+    Wait();
+
+    //  Now delete it.
+    if( m_WorkItem )
+    {
+        IoFreeWorkItem( m_WorkItem );
+    }
+}
+
+BOOLEAN
+KWorkItem::
+Start()
+/*++
+
+Routine Description:
+
+    Enqueue this workitem and acquires a reference on the object.
+
+Arguments:
+
+    None.
+
+Return Value:
+
+    TRUE - a workitem was scheduled.
+
+--*/
+{
+    //  Make sure construction succeeded.
+    if( m_WorkItem )
+    {
+        //  Make sure the work item isn't already in flight and acquire the lock.
+        //  This is to make sure this KWorkItem doesn't get destroyed until
+        //  the callback is complete.
+        if( Acquire() )
+        {
+            //  Schedule the work item.
+            IoQueueWorkItem( m_WorkItem, &KWorkItem::Handler, m_QueueType, this );
+
+            //  Note: Release() is called in Handler.
+            return TRUE;
+        }
+    }
+    return FALSE;
+}
+
+VOID
+KWorkItem::
+Handler(
+    _In_        PDEVICE_OBJECT  IoObject,
+    _In_opt_    PVOID           Context
+)
+/*++
+
+Routine Description:
+
+    Callback thunking function.
+
+    Calls the callback handler registered in the constructor, if one exists.
+    Releases the reference on this object.
+
+Arguments:
+
+    IoObject - 
+        The parent device object.
+    Context -
+        An optional context object.
+
+Return Value:
+
+    void
+
+--*/
+{
+    //  Get our "this" pointer (Me).
+    KWorkItem *Me = (KWorkItem *) Context;
+
+    //  Invoke the callback if one exists.
+    if( Me->m_Callback )
+    {
+        Me->m_Callback( IoObject, Me->m_Context );
+    }
+
+    //  Unlock the work item; allow for destruction or re-enqueing.
+    Me->Release();
+}