/**
  * Write to stream.
  *
  * This method is called in response to fwrite().
  *
  * If there is not enough room in the underlying stream, store as much as
  * possible.
  *
  * Note: Remember to update the current position of the stream by number of
  * bytes that were successfully written.
  *
  * @param string $data Should be stored into the underlying stream.
  * @return int Should return the number of bytes that were successfully stored, or 0 if none could be stored.
  */
 public function stream_write($data)
 {
     return $this->streamWrapper->write($data);
 }