code: func (s *SessionCache) Add() string {
  	strSum := s.salter.DefaultToken()
  
  	err := s.cache.Add(strSum, nil)
  	if err != nil {
  		panic("Something is seriously wrong, a duplicated token was generated")
  	}
  
  	return strSum
  }
docs: // Add creates a new unique token and stores it into current SessionCache
  // instance.
  //
  // The token creation will take at least 200 microseconds, but could normally
  // take 2.5 milliseconds. The token generation function it is built with
  // security over performance.