joinVideoChannel method Null safety

Implementation

void joinVideoChannel() async {
  await value.engine?.enableVideo();
  await value.engine?.enableAudioVolumeIndication(200, 3, true);
  if (value.connectionData!.tokenUrl != null) {
    await _getToken(
      tokenUrl: value.connectionData!.tokenUrl,
      channelName: value.connectionData!.channelName,
      uid: value.connectionData!.uid,
    );
  }
  value.engine?.joinChannel(
    value.connectionData!.tempToken ?? value.generatedToken,
    value.connectionData!.channelName,
    null,
    value.connectionData!.uid ?? 0,
  );
}