(mongodb >=1.11.0)
MongoDB\Driver\Monitoring\CommandFailedEvent::getServiceId — Returns the load balancer service ID for the command
   When the driver is connected to a MongoDB cluster through a load balancer,
   the service ID corresponds to the serviceId field in the
   hello command response.
  
Questa funzione non contiene parametri.
   Returns the load balancer service ID, or null if the driver is not
   connected to a load balancer.
  
