Latency issue

[doisyg]

Hi, thanks for this driver. Overall it is working well.
However I am having a latency issue which is causing some problem for robot navigation.
I can see that there is a delay between the measurements and the time ROS receive them (with rviz). I tried with different frequency and samples_per_scan settings. This is not due to the ethernet com as I can ping the ip of the lidar and get a 0.30 ms delay.
Any idea where this is coming from? Is this delay fixed? Any clue of how to integrate it in the driver?

[doisyg]

Added a very simple latency compensation with an offset: #6
Empirically = to 0.1s on my config.
It would be nice to trace its origin/reduce it/ determine during a proper calibration procdedure what is its real value.