function setTimestamp(?int $timestamp = null) {
        $this->timestamp = (new \DateTime(($timestamp !== null ? '@'.$timestamp : 'now')))->format('c');
        return $this;
    }
function setTimestamp(?int $timestamp = null) {
        $this->timestamp = (new \DateTime(($timestamp !== null ? '@'.$timestamp : 'now')))->format('c');
        return $this;
    }
function setTimestamp ( ? int $ timestamp = null ) { $ this -> timestamp = ( new \ DateTime ( ( $ timestamp !== null ? '@' . $ timestamp : 'now' ) ) ) -> format ( 'c' ) ; return $ this ; }
Set the timestamp of this embed.
@param int|null  $timestamp
@return $this
Set the timestamp of this embed .