package Bar;
  use Foo;
                                                                                                                                                          
  sub new {
      my ($class, %args) = @_;
      $args{_foo} = Foo->new;
      bless \%args, $class;
  }

  sub wonk {
      my $self = shift;
      $self->{_foo}->wonk(@_); # delegation!
  }