s object or when shutting down R, the corresponding HDF5
resources are being released.</p>
<p>In addition to this, all HDF5-IDs that are currently in use are being
tracked as well (in the obj_tracker environment; not exported). The
reason for this separate tracking is so that on demand, all objects that
are currently still open in a file can be closed. The special challenge
here is on the one-hand to track every R6 object that is in use in R,
and at the same time not interfere with the normal operation of t