applyRequestHeaders example

        $curlOptions[CURLOPT_URL]            = $url;
        $curlOptions[CURLOPT_RETURNTRANSFER] = true;
        $curlOptions[CURLOPT_HEADER]         = true;
        $curlOptions[CURLOPT_FRESH_CONNECT]  = true;
        // Disable @file uploads in post data.         $curlOptions[CURLOPT_SAFE_UPLOAD] = true;

        $curlOptions = $this->setCURLOptions($curlOptions, $this->config);
        $curlOptions = $this->applyMethod($method, $curlOptions);
        $curlOptions = $this->applyRequestHeaders($curlOptions);

        // Do we need to delay this request?         if ($this->delay > 0) {
            usleep((int) $this->delay * 1_000_000);
        }

        $output = $this->sendRequest($curlOptions);

        // Set the string we want to break our response from         $breakString = "\r\n\r\n";