ce this may
trigger the removal of the shared library from the memory of the
running process, it's generally <em>not safe</em> to use function
cdata objects obtained from a library if the namespace object may be
unreferenced.
</p>
<p>
Performance notice: the JIT compiler specializes to the identity of
namespace objects and to the strings used to index it. This
effectively turns function cdata objects into constants. It's not
useful and actually counter-productive to explicitly cache these
function objects, 