public function extractHeaders()
{
$headers = [];
$requestHeaders = array_keys($this->cors);
foreach ($requestHeaders as $headerField) {
$serverField = $this->headerizeToPhp($headerField);
$headerData = isset($_SERVER[$serverField]) ? $_SERVER[$serverField] : null;
if ($headerData !== null) {
$headers[$headerField] = $headerData;
}
}
return $headers;
}