/**
* {@inheritdoc}
*
* @param string $command
* @return void
*/
public function start($command)
{
$this->startWorkers($command);
while ($this->isWorking()) {
$worker = $this->getAvailableWorker();
if ($worker && !empty($this->pending)) {
$worker->run(array_shift($this->pending));
}
$this->broker->read();
}
}