AddYears method
Implementation
void AddYears(int years) {
final hr = _thisPtr.ref.vtable
.elementAt(32)
.cast<Pointer<NativeFunction<HRESULT Function(Pointer, Int32 years)>>>()
.value
.asFunction<
int Function(Pointer, int years)>()(_thisPtr.ref.lpVtbl, years);
if (FAILED(hr)) throw WindowsException(hr);
}