Getting PID of queue in horizon with laravel

For different reasons I need to read the PID of the queues of a supervisor in horizon. the problem is that I don't find the information in the library.

I'm able to retrieve all supervisor like this :

public function index(SupervisorRepository $supervisors){
    $supervisors = collect($supervisors->all())->sortBy('name');
    return $supervisors;
}

or all workload(queue) like this :

public function index(WorkloadRepository $workloadRepository){
    $workload = collect($workloadRepository->get())->sortBy('name')->values()->toArray();
    return $workload;
}

but I don't see how I can get the PID of queue by the repository, last but not least I can't run shell command on my server so I must get it by either accessing redis or horizon library