anchor.diff:  
     CompletionMetrics(this.name,
         {required this.availableSuggestions,
  +      this.useNewProtocol = false,
         this.enableFunction,
         this.disableFunction})
  -      : userTag = UserTag(name);
  +      : assert(!(availableSuggestions && useNewProtocol)),
  +        userTag = UserTag(name);
   
     /// Return an instance extracted from the decoded JSON [map].
     factory CompletionMetrics.fromJson(Map<String, dynamic> map) {
  
positive.code:             request,
              metrics.availableSuggestions ? declarationsTracker : null,
              metrics.availableSuggestions ? availableSuggestionsParams : null,
            );
            stopwatch.stop();
  
  
negative.code:   /// run.
    final bool availableSuggestions;
  
    /// A flag indicating whether the new protocol should be used for this run.
    final bool useNewProtocol;
  
    /// The function to be executed when this metrics collector is enabled.
    final void Function()? enableFunction;
  
  