code: def encode_chunk(dataframe):
      
      csv_buffer = six.StringIO()
      dataframe.to_csv(
          csv_buffer,
          index=False,
          header=False,
          encoding="utf-8",
          float_format="%.15g",
          date_format="%Y-%m-%d %H:%M:%S.%f",
      )
  
      # Convert to a BytesIO buffer so that unicode text is properly handled.
      # See: https://github.com/pydata/pandas-gbq/issues/106
      body = csv_buffer.getvalue()
      if isinstance(body, bytes):
          body = body.decode("utf-8")
      body = body.encode("utf-8")
      return six.BytesIO(body)
docs: Return a file-like object of CSV-encoded rows.
  
      Args:
        dataframe (pandas.DataFrame): A chunk of a dataframe to encode