-I've begun to build a formal testing framework. Currently it can mount
-and unmount loopback.pl, and all of the base-level functions have test
-scripts. These need to be fleshed out as problems are noticed.
+Perl 5.8.7 does not support shared subroutine references. Until this is
+fixed, if you use threaded mode, you need to use symbolic references (i.e.
+passing "main::cb" instead of \&cb). This rules out closures, lexical
+subs and that sort of thing, but it does seem to work.