# save all other slots of the typeglob
foreach my $slot (qw( SCALAR ARRAY HASH IO FORMAT )) {
    my $elem = *{ $src->{$symbol} }{$slot};
        next unless defined $elem;
        push @slots, $elem;
    }

    # clear out the source glob
    #       undef &{ *{$src->{$symbol}} } didn't work
    undef $src->{$symbol};

    # replace the sub in the source
    $src->{$symbol} = sub {
        logCall->($symbol, @_);
        return $sub->(@_);
    };

    # replace the other slot elements
    foreach my $elem (@slots) {
        $src->{$symbol} = $elem;
    }
}