anchor.diff:      bool bubbles,
       bool cancelable,
       bool currentTarget,
  -    bool _defaultPrevented,
  -    dynamic _preventDefault,
  +    bool defaultPrevented,
  +    dynamic preventDefault,
       dynamic stopPropagation,
       num eventPhase,
       bool isTrusted,
  
positive.code:       bool bubbles,
        bool cancelable,
        bool currentTarget,
        bool _defaultPrevented,
        dynamic _preventDefault,
        dynamic stopPropagation,
        num eventPhase,
        bool isTrusted,
  
negative.code:             bubbles,
              cancelable,
              currentTarget,
              defaultPrevented,
              preventDefault,
              stopPropagation,
              eventPhase,
              isTrusted,
  