fix bug when tracks is null
@@ -181,7 +181,7 @@ class Client extends EventEmitter {
logger.debug('subscribe rid => $rid, mid => $mid, tracks => ${tracks.toString()}');
Completer completer = new Completer<Stream>();
var codec = "";
- tracks.forEach((trackID,trackInfoArr) async {
+ tracks?.forEach((trackID,trackInfoArr) async {
logger.debug('trackInfoArr=$trackInfoArr');
for(var i=0; i<trackInfoArr.length; i++){
