Optimization - 1: Cost of Forwarding

template parameter T	TypeTraits<T>::ParameterType
U	U if U is primitive; otherwise const U&
const U	U if U is primitive; otherwise const U&
U&	U&
const U&	const U&

class TypeTraits
{
...
  template <class U> struct ReferenceTraits
  {
    enum { result = false };
    typedef U ReferredType;
  };
        
  template <class U> struct ReferenceTraits<U&>
  {
    enum { result = true };
    typedef U ReferredType;
  };
  ...        
public:
  ...
  enum { isReference = ReferenceTraits<T>::result };
  typedef typename ReferenceTraits<T>::ReferredType ReferredType;
  ...
};