template<typename Signature, typename OutSignal = unfused, 
         typename Combiner = boost::last_value<typename boost::function_traits<Signature>::result_type>, 
         typename Group = int, typename GroupCompare = std::less<Group> > 
class storage {
public:
  // types
  typedef unspecified parameter_types;
  typedef unspecified storable_types; 
  typedef unspecified storable_vector;

  // construct/copy/destruct
  template<typename Seq> storage(const Seq &);
  storage();

  // public member functions
  void open() ;
  void close() ;
  base_type::signal_type::result_type send() ;
  base_type::signal_type::result_type send(const boost::fusion::vector<> &) ;
  const storable_vector & stored_vector() ;
  template<int N> 
    boost::fusion::result_of::at_c< storable_vector, N >::type at() ;
  template<int N> boost::mpl::at_c< parameter_types, N >::type value_at() ;
  template<int N> slot_selector at_slot() ;
  template<int N> slot_selector value_at_slot() ;

  // protected member functions
  storable_vector & stored() ;
};