/**
* Parses an article from a string.
*/
public static function parse(string $data) : self
{
$separator = strpos($data, "\r\n\r\n");
if ($separator === false) {
throw new FormatException('Invalid article format');
}
$headers = HeaderBag::parse(substr($data, 0, $separator + 2));
$body = substr($data, $separator + 4);
return new self($body, $headers);
}