Performance reviewing for useRef and useState.

[chhsiao1981]

Currently there are many useRef in the code.

https://github.com/chhsiao1981/react-reducer-utils/blob/main/src/useReducer.ts#L30 (dispatchMap)
https://github.com/chhsiao1981/react-reducer-utils/blob/main/src/thunkReducer.ts#L52 (state)

We even have a global state for the shared state:

https://github.com/chhsiao1981/react-reducer-utils/blob/main/src/useReducer.ts#L11 (dispatchMap)
https://github.com/chhsiao1981/react-reducer-utils/blob/main/src/thunkReducer.ts#L9 (state)

We also have useState in the code:

https://github.com/chhsiao1981/react-reducer-utils/blob/main/src/thunkReducer.ts#L46

Unsure whether there is some redundancy with such setting.