code: def _get_next_chunk(fp, previously_read_position, chunk_size):
      
      seek_position, read_size = _get_what_to_read_next(fp, previously_read_position, chunk_size)
      fp.seek(seek_position)
      read_content = fp.read(read_size)
      read_position = seek_position
      return read_content, read_position
docs: Return next chunk of data that we would from the file pointer.
  
      Args:
          fp: file-like object
          previously_read_position: file pointer position that we have read from
          chunk_size: desired read chunk_size
  
      Returns:
          (bytestring, int): data that has been read in, the file pointer position where the data has been read from