public function setProxy($host, $port = 8080, $user = null, $pass = null)
{
$uri = new Uri(['scheme' => 'tcp', 'host' => $host, 'port' => $port]);
if (!empty($user)) {
$uri->user = $user;
if (!empty($pass)) {
$uri->pass = $pass;
}
}
$this->setOption('proxy', $uri->build());
}