public function getProxyUriString()
    {
        $uri = isset($this->proxyConf['proto']) ? $this->proxyConf['proto'] : "http";
        // https://curl.haxx.se/libcurl/c/CURLOPT_PROXY.html
        $supportedProtocols = array(
            'http',
            'https',
            'socks4',
            'socks4a',
            'socks5',
            'socks5h',
        );

        if (in_array($uri, $supportedProtocols) === false) {
            // WPCS: XSS OK.
            echo "Unknown proxy protocol '" . $this->proxyConf['proto'] . "', supported protocols are " . implode(", ", $supportedProtocols) . PHP_EOL;
        }

        $uri .= "://";
        $uri .= isset($this->proxyConf['address']) ? $this->proxyConf['address'] : "localhost";

        if (isset($this->proxyConf['address']) === false) {
            // WPCS: XSS OK.
            echo "warning: proxy address not set defaulting to localhost" . PHP_EOL;
        }

        $uri .= ":";
        $uri .= isset($this->proxyConf['port']) ? $this->proxyConf['port'] : "1080";

        if (isset($this->proxyConf['address']) === false) {
            // WPCS: XSS OK.
            echo "warning: proxy port not set defaulting to 1080" . PHP_EOL;
        }

        return $uri;
    }