'Return a :class:`swift.common.swob.Response` class compatible
"`app_iter`" object as defined by
:class:`swift.obj.diskfile.DiskFileReader`.
For this implementation, the responsibility of closing the open file
is passed to the :class:`swift.obj.diskfile.DiskFileReader` object.
:param keep_cache: caller\'s preference for keeping data read in the
OS buffer cache
:param _quarantine_hook: 1-arg callable called when obj quarantined;
the arg is the reason for quarantine.
Default is to ignore it.
Not needed by the REST layer.
:returns: a :class:`swift.obj.diskfile.DiskFileReader` object'

def reader(self, keep_cache=False, _quarantine_hook=(lambda m: None)):

    dr = self.reader_cls(self._fp, self._data_file, int(self._metadata['Content-Length']), self._metadata['ETag'], self._disk_chunk_size, self._manager.keep_cache_size, self._device_path, self._logger, use_splice=self._use_splice, quarantine_hook=_quarantine_hook, pipe_size=self._pipe_size, diskfile=self, keep_cache=keep_cache)
    self._fp = None
    return dr
