private void AppendDescriptors( Diffgram diffgram )
        {
            IDictionaryEnumerator en = _moveDescriptors.GetEnumerator();
            while ( en.MoveNext() )
            diffgram.AddDescriptor( new OperationDescrMove( (ulong)en.Value ) );
            NamespaceChange nsChange = _namespaceChangeDescr;
            while ( nsChange != null )
            {
            diffgram.AddDescriptor( new OperationDescrNamespaceChange( nsChange ) );
            nsChange = nsChange._next;
            }

            PrefixChange prefixChange = _prefixChangeDescr;
            while ( prefixChange != null )
            {
            diffgram.AddDescriptor( new OperationDescrPrefixChange( prefixChange ) );
            prefixChange = prefixChange._next;
            }
        }