encode method Null safety

Implementation

Object encode() {
  final Map<Object?, Object?> pigeonMap = <Object?, Object?>{};
  pigeonMap['itemId'] = itemId;
  pigeonMap['playbackDuration'] = playbackDuration;
  pigeonMap['startTime'] = startTime;
  pigeonMap['media'] = media?.encode();
  pigeonMap['autoplay'] = autoplay;
  pigeonMap['preloadTime'] = preloadTime;
  return pigeonMap;
}