Tar download from HEASARC hanging?

When I use `Heasarc.download_data` with host=`heasarc`, I see an empty tar file being created and then the query hanging for a long time. Is it the expected behavior?

Start by reproducing the hang with Heasarc.download_data using host="heasarc" and observe the empty tar file and request behavior. Determine whether the behavior is expected or a defect, then document the expected outcome and add a regression test if the repository provides a suitable test entry point.

Written by the indexing model from the issue text.