It seems multicam example of librealsense2 is not working here.
After I build multicam example, the app just hangup. No error can be seen in Xcode.
A similar thing happens when I try to access res2::device inside device_list.

auto deviceList = _ctx->query_devices();
if(deviceList.size() > 0) {
device = deviceList[0];
}

Am I missing something?