src/HTTP2.php
public function date($time = null)
    {
        if (!isset($time)) {
            $time = time();
        } elseif (!is_numeric($time) && (-1 === $time = strtotime($time))) {
            return false;
        }

        // RFC822 or RFC850
        $format = ini_get('y2k_compliance') ? 'D, d M Y' : 'l, d-M-y';

        return gmdate($format .' H:i:s \G\M\T', $time);
    }
public function date($time = null)
    {
        if (!isset($time)) {
            $time = time();
        } elseif (!is_numeric($time) && (-1 === $time = strtotime($time))) {
            return false;
        }

        // RFC822 or RFC850
        $format = ini_get('y2k_compliance') ? 'D, d M Y' : 'l, d-M-y';

        return gmdate($format .' H:i:s \G\M\T', $time);
    }
Formats a RFC compliant GMT date HTTP header.  This function honors the
"y2k_compliance" php.ini directive and formats the GMT date corresponding
to either RFC850 or RFC822.

@param mixed $time unix timestamp or date (default = current time)

@return string|boolean GMT date string, or FALSE for an invalid
$time parameter