Device.load() get nothing at OnSuccess

I use the 3.1.1 LibraryMediaSoupClient and the newest WebRTC Code buid apk in Android device

But I can’t get any desc data at PeerConnection::CreateSessionDescriptionObserver:: OnSuccess() callback when called Device.load() method.

void PeerConnection::CreateSessionDescriptionObserver::OnSuccess(
webrtc::SessionDescriptionInterface* desc)
std::string out;
MSC_WARN("OnSuccess(): %s. sdp: %s", out.c_str(), sdp.c_str());//This print nothing.

And at source code), can print desc.

void OnSuccess(SessionDescriptionInterface* desc) override {
was_called_ = true;
#endif // RTC_DCHECK_IS_ON
// Completing the operation before invoking the observer allows the observer
// to execute SetLocalDescription() without delay.
std::string out;
RTC_LOG(LS_WARNING) << "OnSuccess() description[" << out << "]";

When I change the ①and② process order, out print nothing too.

Did any body knows why?
The new WebRTC code changed too many, can any body tell me what do I need modify?
Thanks very much.

Why do you use latest WebRTC code? Read the libmesiasoupclient docs.

Got it. It need be build with m87&4147. I will try it soon.
Thanks for help.

It resolve my problem.Thanks for your help very much!