title: Link external raw file to hdf5 file with h5py
body: <p>I work a lot with binary flat files and they need to remain in their current format to work with legacy codes, however I would also like to be able to use some of the features of HDF5 files with the attributes and groups. I see in the HDF5 <a href="https://www.hdfgroup.org/HDF5/doc/UG/HDF5_Users_Guide-Responsive%20HTML5/index.html#t=HDF5_Users_Guide%2FDatasets%2FHDF5_Datasets.htm%23TOC_5_5_4_External_Storagebc-19&amp;rhtocid=5.3.0_4" rel="nofollow">documentation 5.5.4</a> that external data can be linked in. Is there a straight-forward way to create the HDF5 files and add the external links with h5py?</p>