addMonths method
Implementation
void addMonths(int months) {
final hr = ptr.ref.vtable
.elementAt(41)
.cast<
Pointer<NativeFunction<HRESULT Function(Pointer, Int32 months)>>>()
.value
.asFunction<
int Function(Pointer, int months)>()(ptr.ref.lpVtbl, months);
if (FAILED(hr)) throw WindowsException(hr);
}