private function __sortMetaHeadersCmp($a, $b)
	{
		$lenA = strpos($a, ':');
		$lenB = strpos($b, ':');
		$minLen = min($lenA, $lenB);
		$ncmp = strncmp($a, $b, $minLen);
		if ($lenA == $lenB) return $ncmp;
		if (0 == $ncmp) return $lenA < $lenB ? -1 : 1;
		return $ncmp;
	}