anchor.diff:  /// used, through a call to `WindowsDeleteString()`.
   /// {@category winrt}
   Pointer<IntPtr> convertToHString(String string) {
  -  final hString = allocate<IntPtr>();
  -
  +  final hString = calloc<IntPtr>();
     // Create a HSTRING representing the object
     final hr = WindowsCreateString(Utf16.toUtf16(string), string.length, hString);
     if (FAILED(hr)) {
  
positive.code: /// {@category winrt}
  String convertFromHString(Pointer<IntPtr> hstring) {
    final stringLength = allocate<Uint32>();
    final stringPtr = WindowsGetStringRawBuffer(hstring.value, stringLength);
    final dartString = stringPtr.unpackString(stringLength.value);
  
    free(stringLength);
  
    return dartString;
  }
  
  /// Takes a Dart String and converts it to an `HSTRING` (a WinRT String),
  
negative.code: /// {@category winrt}
  Pointer<IntPtr> CreateObject(String className, String iid) {
    final hstrClass = allocate<IntPtr>();
    final lpClassName = TEXT(className);
    final inspectablePtr = calloc<Pointer>();
    final riid = calloc<GUID>();
    final classPtr = calloc<IntPtr>();
  
    try {
      // Create a HSTRING representing the object
      var hr = WindowsCreateString(
          Utf16.toUtf16(className), className.length, hstrClass);
      if (FAILED(hr)) {
        throw WindowsException(hr);
      }
      // Activates the specified Windows Runtime class. This returns the WinRT
      // IInspectable interface, which is a subclass of IUnknown.
      hr = RoActivateInstance(hstrClass.value, inspectablePtr);
      if (FAILED(hr)) {
        throw WindowsException(hr);
      }
  
      // Create an IID for the interface required
      hr = IIDFromString(TEXT(iid), riid);
      if (FAILED(hr)) {
        throw WindowsException(hr);
      }
  
      // Now use IInspectable to navigate to the relevant interface
      final inspectable = IInspectable(inspectablePtr.cast());
      hr = inspectable.QueryInterface(riid, classPtr);
      if (FAILED(hr)) {
        throw WindowsException(hr);
      }
  
      // Return a pointer to the relevant class
      return classPtr;
    } finally {
      free(riid);
      free(inspectablePtr);
      free(lpClassName);
      free(hstrClass);
    }
  }
  