PHPPM\ProcessManager::replaceHeader PHP Method

    protected function replaceHeader($header, $headersToReplace)
    {
        $result = $header;
        foreach ($headersToReplace as $key => $value) {
            if (false !== ($headerPosition = stripos($result, $key . ':'))) {
                //check how long the header is
                $length = strpos(substr($header, $headerPosition), "\r\n");
                $result = substr_replace($result, "{$key}: {$value}", $headerPosition, $length);
            } else {
                //$key is not in header yet, add it at the end
                $end = strpos($result, "\r\n\r\n");
                $result = substr_replace($result, "\r\n{$key}: {$value}", $end, 0);
            }
        }
        return $result;
    }