IMU doesn't publish messages

[XuanTr]

Hi,
I have installed this simulator. It's ok now, but i can't control using virtual joystick. (rotors_joy_interface/key_joystick.py)
After i view source code, i see that
topic > imu
is not published.
I think it because librotors_gazebo_imu_plugin.so not publish events, but don't know why it doesn't publish messages.
I have checked rostopic echo /quad/imu and it show nothing.

The bellow callback is not called.

I also checked librotors_gazebo_imu_plugin, it has published imu data on ~/quad/imu but callback is still not called.
I find that the gazebo_imu_plugin has published but with type gz_sensor_msgs::Imu, not sensor_msgs::Imu.

So, how to fix it.