code: public void createDataChannel() {
          if (null != callReference) {
              RespokeCall call = callReference.get();
              if (null != call) {
                  PeerConnection peerConnection = call.getPeerConnection();
                  dataChannel = peerConnection.createDataChannel("respokeDataChannel", new DataChannel.Init());
                  dataChannel.registerObserver(this);
              }
          }
      }
docs: Establish a new direct connection instance with the peer connection for the call. This is used internally to the SDK and should not be called directly by your client application.