private function initializeIdleTimeout(SocketPoolStruct $poolStruct)
{
if (isset($poolStruct->idleWatcher)) {
\Amp\enable($poolStruct->idleWatcher);
} else {
$poolStruct->idleWatcher = \Amp\once(function () use($poolStruct) {
$this->unloadSocket($poolStruct->uri, $poolStruct->id);
}, $poolStruct->msIdleTimeout);
}
}