public function withSocks5(string $host, int $port, ?string $username, ?string $password): self
    {
        $this->proxy = [
            'socks5_host' => $host,
            'socks5_port' => $port,
            'socks5_username' => $username,
            'socks5_password' => $password,
        ];

        return $this;
    }