Follow https://github.com/ouster-lidar/ouster-ros/blob/ros2/README.md
Hostname: os-122333000772.local
Error1 : Couldn't resolve hostname
Solution: https://github.com/ouster-lidar/ouster_example/issues/137#issuecomment-578435555
0 points from 0 msg( in rviz ) soln:
- the ref frame of grid & pointcloud2d should be set to os_sensor
- the fixed framed should also be os_sensor