Method register

redis.go:258–268

register adds or replaces the callback associated with id. Re-registering an existing id overwrites the previous callback in place; new ids are appended to the invocation order.

(id string, fn func() error)

// an existing id overwrites the previous callback in place; new ids are
// appended to the invocation order.
func (h *onCloseHooks) register(id string, fn func() error) {
	h.mu.Lock()
	defer h.mu.Unlock()
	if h.hooks == nil {
		h.hooks = make(map[string]func() error)
	}
	if _, exists := h.hooks[id]; !exists {
		h.order = append(h.order, id)
	}
	h.hooks[id] = fn
}

// unregister removes the callback associated with id, if any. It is kept
// for API symmetry with register so future callers (e.g. dynamic hook