Reads or downloads the received blob from the system.

def _download_chunk_with_retries(self, chunk_offset, chunk_size,
                                     retries=3, retry_wait=1):
        """Reads or downloads the received blob from the system."""
        import azure
        while True:
            try:
                chunk = self._download_chunk(chunk_offset, chunk_size)
            except azure.WindowsAzureError:
                if retries > 0:
                    retries = retries - 1
                    time.sleep(retry_wait)
                else:
                    raise
            else:
                return chunk