copyToNativePointer method
Copy the Uint8List into a freshly allocated Pointer<Uint8>.
Implementation
Pointer<Uint8> copyToNativePointer() {
  final Pointer<Uint8> ptr = malloc<Uint8>(length);
  final Uint8List view = ptr.asTypedList(length);
  view.setAll(0, this);
  return ptr;
}