fix(#4247): use useTransition to track mutation isMutating

[SukkaW]

When trigger is called within a transition (e.g. React's

action prop), any state update inside the transition (a.k.a. the trigger function) will be deferred/delayed until the transition finishes, which means the async function is resolved/rejected.

However, we don't want the isMutating update (false -> true -> false) to be deferred/delayed, otherwise the UI won't be able to reflect the loading state.

One way to do this is to use useTransition. In React 19, useTransition's isPending can be used to track async transition resolved/rejected state. And isPending would be an urgent update that won't be deferred/delayed.

React 18's useTransition doesn't support async function tracking. In React 16 and 17, there is no useTransition at all. A polyfill is introduced.

Alternative

Technically, we can use flushSync to force an urgent update, but it can be dangerous and may cause undefined behavior when invoked within a transition. It may even cause a Suspense boundary fallback to reappear, which is not ideal. Also, flushSync is a react-dom API.

Caveat

We lose the re-render optimization for isMutating. Now the component will always re-render when isPending/isMutaing changes no matter the component actually read isMutaing field or not.