Brief Digression: Tracing Again

In Part I, we saw a trace utility
- It wrapped each function inside a tracing wrapper:

            my $real_func = \&*$func_name;
            *{$caller . "::$func_name"} = sub {
              print "$func_name(@_)\n";
              $real_func->(@_);
            };

If $real_func depends on caller, it could get confused
It will notice that it was called from the wrapper, not from the real caller
Solution:

            {$caller . "::$func_name"} = sub {
              print "$func_name(@_)\n";
              goto &$real_func;
            };