phpseclib\System\SSH\Agent::startSSHForwarding PHP Méthode

    function startSSHForwarding($ssh)
    {
        if ($this->forward_status == self::FORWARD_NONE) {
            $this->forward_status = self::FORWARD_REQUEST;
        }
    }

 /**
  * {@inheritdoc}
  */
 public function connect()
 {
     $serverConfig = $this->getConfiguration();
     $this->sftp = new SFTP($serverConfig->getHost(), $serverConfig->getPort(), 3600);
     switch ($serverConfig->getAuthenticationMethod()) {
         case Configuration::AUTH_BY_PASSWORD:
             $result = $this->sftp->login($serverConfig->getUser(), $serverConfig->getPassword());
             break;
         case Configuration::AUTH_BY_IDENTITY_FILE:
             $key = new RSA();
             $key->setPassword($serverConfig->getPassPhrase());
             $key->loadKey(file_get_contents($serverConfig->getPrivateKey()));
             $result = $this->sftp->login($serverConfig->getUser(), $key);
             break;
         case Configuration::AUTH_BY_PEM_FILE:
             $key = new RSA();
             $key->loadKey(file_get_contents($serverConfig->getPemFile()));
             $result = $this->sftp->login($serverConfig->getUser(), $key);
             break;
         case Configuration::AUTH_BY_AGENT:
             $key = new Agent();
             $key->startSSHForwarding(null);
             $result = $this->sftp->login($serverConfig->getUser(), $key);
             break;
         default:
             throw new RuntimeException('You need to specify authentication method.');
     }
     if (!$result) {
         throw new RuntimeException('Unable to login with the provided credentials.');
     }
 }