`VideoCompress.getByteThumbnail` extract the same frame at different position

```
final uint8list = await VideoCompress.getByteThumbnail(
videopath,
position: 0
);
final uint8list = await VideoCompress.getByteThumbnail(
videopath,
position: 10
);
final uint8list = await VideoCompress.getByteThumbnail(
videopath,
position: 100
);
final uint8list = await VideoCompress.getByteThumbnail(
videopath,
position: 1000
);
```
except `position: 0` `VideoCompress.getByteThumbnail` returns the same frame each time on MacOS
it's not clear how `VideoCompress.getByteThumbnail` selects the frame to extract, does it use keyframe? the extracted keyframe doesn't match the `position` on macOS