public function close()
{
if ($this->out !== null) {
$this->out->removeAllListeners();
}
if ($this->in !== null) {
$this->in->removeAllListeners();
}
if ($this->err !== null) {
$this->err->removeAllListeners();
}
$this->process->removeAllListeners();
if ($this->process->isRunning()) {
$this->process->terminate();
}
}
