code: func (s *Subscription) Unsubscribe() error {
  	if s == nil {
  		return ErrBadSubscription
  	}
  	s.mu.Lock()
  	conn := s.conn
  	s.mu.Unlock()
  	if conn == nil {
  		return ErrBadSubscription
  	}
  	if conn.IsDraining() {
  		return ErrConnectionDraining
  	}
  	return conn.unsubscribe(s, 0, false)
  }
docs: // Unsubscribe will remove interest in the given subject.