MongoDB\Driver\Monitoring\addSubscriber Registers a new monitoring event subscriber &reftitle.description; voidMongoDB\Driver\Monitoring\addSubscriber MongoDB\Driver\Monitoring\Subscribersubscriber Registers a new monitoring event subscriber with the driver. Registered subscribers will be notified of monitoring events through specific methods. If the object is already registered, this function is a no-op. &reftitle.parameters; subscriber (MongoDB\Driver\Monitoring\Subscriber) A monitoring event subscriber object to register. &reftitle.returnvalues; &return.void; &reftitle.errors; &mongodb.throws.argumentparsing; &reftitle.seealso; MongoDB\Driver\Monitoring\Subscriber MongoDB\Driver\Monitoring\CommandSubscriber MongoDB\Driver\Monitoring\removeSubscriber