code: def _openStream(dataUrl,
                    isBlocking,  # pylint: disable=W0613
                    maxTimeout,  # pylint: disable=W0613
                    bookmark,
                    firstRecordIdx):
      
      filePath = dataUrl[len(FILE_PREF):]
      if not os.path.isabs(filePath):
        filePath = os.path.join(os.getcwd(), filePath)
      return FileRecordStream(streamID=filePath,
                              write=False,
                              bookmark=bookmark,
                              firstRecord=firstRecordIdx)
docs: Open the underlying file stream
      This only supports 'file://' prefixed paths.
  
      :returns: record stream instance
      :rtype: FileRecordStream