public function setWorkerPoolSize($size) {
		if ($this->created) {
			throw new WorkerPoolException('Cannot set the Worker Pool Size for a created pool.');
		}
		$size = (int)$size;
		if ($size <= 0) {
			throw new \InvalidArgumentException('"' . $size . '" is not an integer greater than 0.');
		}
		$this->workerPoolSize = $size;
		return $this;
	}