HttpRequest::fetchHeaders

private function fetchHeaders(Server $server)
{
	$headers = [];
	foreach ($server as $name => $value)
	{
		if (str_starts_with($name, 'HTTP_'))
		{
			$headerName = substr($name, 5);
			$headers[$headerName] = $value;
		}
		elseif (in_array($name, ['CONTENT_TYPE', 'CONTENT_LENGTH'], true))
		{
			$headers[$name] = $value;
		}
	}

	return $this->normalizeHeaders($headers);
}