code: public function getFreeAndBusyWorkers() {
  		$free = $this->getFreeWorkers();
  		return array(
  			'free' => $free,
  			'busy' => $this->workerPoolSize - $free,
  			'total' => $this->workerPoolSize
  		);
  	}
docs: Returns the number of busy and free workers
  
  This function collects all the information at once.
  @return array with the keys 'free', 'busy', 'total'