code: public <T> Object getBeanKey(Contextual<T> bean)
      {
          if (passivationCapable)
          {
              // if the
              return ((PassivationCapable) bean).getId();
          }
  
          return bean;
      }
docs: If the context is a passivating scope then we return
  the passivationId of the Bean. Otherwise we use
  the Bean directly.
  @return the key to use in the context map