public IClassifier GetClassifier(ITextBuffer textBuffer)
        {
            Debug.Assert(_classificationRegistry != null);

              var classifierKey = typeof(UsageClassifier);
              UsageClassifier classifier;
              if (!textBuffer.Properties.TryGetProperty(classifierKey, out classifier))
              {
            classifier = new UsageClassifier(_classificationRegistry, textBuffer);
            textBuffer.Properties.AddProperty(classifierKey, classifier);
              }
              return classifier;
        }
        public IClassifier GetClassifier(ITextBuffer textBuffer)
        {
            Debug.Assert(_classificationRegistry != null);

            var             classifierKey = typeof(UsageClassifier);
            UsageClassifier classifier;

            if (!textBuffer.Properties.TryGetProperty(classifierKey, out classifier))
            {
                classifier = new UsageClassifier(_classificationRegistry, textBuffer);
                textBuffer.Properties.AddProperty(classifierKey, classifier);
            }
            return(classifier);
        }