public ICompletionSource TryCreateCompletionSource(ITextBuffer buffer)
        {
            Func <CodeCompletionSource> sc = delegate() {
                ILabelGraph labelGraph = AsmDudeToolsStatic.Get_Label_Graph(buffer, this._aggregatorFactory, this._docFactory, this._contentService);
                return(new CodeCompletionSource(buffer, labelGraph));
            };

            return(buffer.Properties.GetOrCreateSingletonProperty(sc));
        }