showThumbnailPreview method
Implementation
void showThumbnailPreview(double progress) {
progress = progress.clamp(0.0, 1.0);
final duration = kState.duration.value.inSeconds;
if (duration <= 0) return;
final target = Duration(seconds: (progress * duration).round());
previewThumbnailController.setCurrentTime(target.inMilliseconds);
}