code: protected function writeInteger($fileHandle, $integer)
      {
          return $this->writeBytes($fileHandle, pack($this->useBigEndian ? 'N' : 'V', (int) $integer));
      }
docs: Writes a 4-byte integer.
  @param resource $fileHandle to write to
  @param int $integer to be written
  @return int how many bytes are written