code: func (m *MemoryStorer) ResetExpiry(key string) error {
  	m.mut.RLock()
  	session, ok := m.sessions[key]
  	m.mut.RUnlock()
  	if !ok {
  		return errNoSession{}
  	}
  
  	session.expires = time.Now().UTC().Add(m.maxAge)
  	m.sessions[key] = session
  	return nil
  }
docs: // ResetExpiry resets the expiry of the key