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

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