/// <summary>
 /// Adds an attribute descriptor.
 /// </summary>
 /// <param name="ad">the attribute descriptor to Add
 /// </param>
 public virtual void AddAttributeDescriptor(AttributeDescriptor ad)
 {
     attributeNameDescriptorMap[ad.Name]     = ad;
     attributeHandleDescriptorMap[ad.Handle] = ad;
 }
 /// <summary> Notifies this object that an attribute of interest has been
 /// added to the descriptor manager.
 ///
 /// </summary>
 /// <param name="ad">the attribute descriptor
 /// </param>
 protected internal virtual void AttributeAdded(AttributeDescriptor ad)
 {
     AddAttributeDescriptor(ad);
 }