public function append($string, $length = null)
    {
        $this->end();
        return $this->write($string, $length);
    }
public function append($string, $length = null)
    {
        $this->end();
        return $this->write($string, $length);
    }
public function append ( $ string , $ length = null ) { $ this -> end ( ) ; return $ this -> write ( $ string , $ length ) ; }
Append data to the stream.

@param  string  $string The string that is to be written.
@param  integer $length If the length argument is given, writing will stop after length bytes have
been written or the end of string if reached, whichever comes first.
@return integer         Number of bytes written
Append data to the stream .