fix(hesai_hw_monitor): fix 2s drops issue - again

[mojomex]

PR Type

• Bug Fix

Related Links

• fix(hesai_hw_interface): change to synchronous requests to prevent undefined sensor behavior #126 -- last attempted fix
• TIER IV INTERNAL LINK -- detailed troubleshooting

Description

This PR fixes the OT128's 2s UDP packet drop issue (again, this time for node containers).
The culprit was a race condition between the HW monitor's OnHesaiStatusTimer() and OnHesaiLidarMonitorTimer() callbacks, which both access the non-thread-safe HW interface.
(Thread-safety will probably be fixed by #131 as the SendReceive() function should be thread-safe there, as a side-effect of the other fixes made.)

Due to the race condition, the callbacks got into a deadlock, causing all TCP communication from HW monitor to stop. HW monitor is the only source of constant TCP traffic to the sensor (once per diag_span, default 1s) and is thought to refresh the sensor's ARP cache. When the monitor stops, after 1 minute the sensor sends 2 duplicate ARP requests (which are presumably a bug on the sensor side), causing the sensor to stop sending UDP packets for 2s.

The fix in this PR is to merge the two above-mentioned callbacks into a unified one:

[this](){
  OnHesaiStatusTimer();
  OnHesaiLidarMonitorTimer();
}

This gets rid of the sensor's duplicate ARP requests and 2s drops once per minute.

Review Procedure

Run Nebula with OT128 once with, once without this PR (using hesai_launch_component.launch.xml) and confirm in Wireshark -> Statistics -> I/O Graphs that once per minute there is a 2s drop without this PR, and no such drop with this PR.

Remarks

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