sub rarelyusedfunction
{
        my $self = shift;
        my $cl = Foo::CodeLoader->new();

        $cl->load('DDS');

        my $dds = Data::Dump::Streamer->new;
        $dds->Dump($self)->Out();

}

##</code><code>##

sub rarelyusedfunction
{
        my $self = shift;
        if ( eval { require Data::Dump::Streamer; 1 } ) {
           return scalar Data::Dump::Streamer::Dump($self)->Out();
        } else {
           warn "**DANGER** Falling back to Data::Dumper as DDS"
                . " isn't available";
           require Data::Dumper;
           return Data::Dumper::Dumper($self)
        }

}

##</code><code>##

if ( eval { require Foo; 1 } ) { .. } else { ... }