anchor.diff:      }
     }
   
  +  /// Clears the contents of a given field.
     void clearField(int tagNumber) {
       _fieldValues.remove(tagNumber);
     }
  
positive.code:     }
    }
  
    void mergeFromBuffer(
        List<int> input,
        [ExtensionRegistry extensionRegistry = ExtensionRegistry.EMPTY]) {
  
negative.code:   }
  
  
    /// Merges field values from [data], a JSON object, encoded as described by
    /// [GeneratedMessage.writeToJson].
    void mergeFromJson(
        String data,
        [ExtensionRegistry extensionRegistry = ExtensionRegistry.EMPTY]) {
      _mergeFromJson(JSON.decode(data), extensionRegistry);
    }
  
    /// Merges field values from a JSON object represented as a Dart map.
    ///
    /// The encoding is described in [GeneratedMessage.writeToJson].
    void mergeFromJsonMap(
        Map<String, dynamic> json,
        [ExtensionRegistry extensionRegistry = ExtensionRegistry.EMPTY]) {
      _mergeFromJson(json, extensionRegistry);
    }
  
    /// Adds an extension field value to a repeated field.
    ///
    /// The backing [List] will be created if necessary.
    void addExtension(Extension extension, var value) {
      _checkExtension(extension);
      if ((extension.type & _REPEATED_BIT) == 0) {
  