anchor.diff:  /// This is the main metrics computer class for code completions. After the
   /// object is constructed, [computeCompletionMetrics] is executed to do analysis
   /// and print a summary of the metrics gathered from the completion tests.
  -class CompletionCoverageMetrics {
  +class CompletionMetricsComputer {
     final String _rootPath;
   
     String _currentFilePath;
  
positive.code: 
    /// The int to be returned from the [compute] call.
    int resultCode;
  
    var completionCounter = Counter('successful/ unsuccessful completions');
    var completionMissedTokenCounter =
  
negative.code:       MeanReciprocalRankComputer('type member completions');
    var nonTypeMemberMRRComputer =
        MeanReciprocalRankComputer('non-type member completions');
  }
  