private function parseHeaders($header)
{
$headers = [];
foreach (explode("\r\n", $header) as $line) {
if (strpos($line, ':') !== false) {
list($key, $value) = explode(': ', $line);
$key = str_replace('-', '_', strtolower($key));
$headers[$key] = trim($value);
}
}
return $headers;
}