public function putDate(int $timestamp = null): self
    {
        if (null === $timestamp) {
            $date = gmdate('D, d M Y H:i:s');
        } else {
            $date = gmdate('D, d M Y H:i:s', $timestamp);
        }

        $this->put('Date', $date . ' GMT');
        return $this;
    }
public function putDate(int $timestamp = null): self
    {
        if (null === $timestamp) {
            $date = gmdate('D, d M Y H:i:s');
        } else {
            $date = gmdate('D, d M Y H:i:s', $timestamp);
        }

        $this->put('Date', $date . ' GMT');
        return $this;
    }
public function putDate ( int $ timestamp = null ) : self { if ( null === $ timestamp ) { $ date = gmdate ( 'D, d M Y H:i:s' ) ; } else { $ date = gmdate ( 'D, d M Y H:i:s' , $ timestamp ) ; } $ this -> put ( 'Date' , $ date . ' GMT' ) ; return $ this ; }
adds a date header

@param   int  $timestamp  timestamp to use as date, defaults to current timestamp
@return  \stubbles\peer\HeaderList
adds a date header