newPlayer method
Implementation
@override
Future<String> newPlayer({String? url}) async {
final playerId = DateTime.now().microsecondsSinceEpoch.toString();
final player = VideoJsPlayer(playerId, listener: _rootPlaybackListener, plugin: this);
webVideoPlayers[playerId] = player;
stateNotifier.getOrAddPlayerNotifier(playerId);
return playerId;
}