anchor.diff:  VTextInput textInput({
     Object key,
     String value,
  +  String placeholder,
  +  bool autofocus,
     String id,
     Map<String, String> attributes,
     List<String> classes,
  
positive.code:   return new VTextInput(
        key: key,
        value: value,
        id: id,
        attributes: attributes,
        classes: classes,
  
negative.code:     if (_value != null) {
        ref.value = _value;
      }
      if (placeholder != null) {
        ref.placeholder = placeholder;
      }
      if (autofocus != null) {
        ref.autofocus = true;
      }
    }
  
    void update(VTextInput other, Context context) {
  