Memoize `connect` response callback functions

[sdemjanenko]

I ran into this issue when using the file-upload package, but I think it applies to all components. The code examples

const api = fileUpload.connect(state, send, normalizeProps)

returns a new api object every time a component renders. Ideally this would be memoized so child components can optimize their rendering if they so choose. Memoizing the callback functions separately would also be useful. I ran into an issue where I had code that updated the machine's state if a parent component provided a new value

useEffect(() => {
  api.setFiles(value)
}, [value, api.setFiles])

Because api.setFiles is new every time the component renders, the useEffect gets run (even when the value is unchanged).

I think adding memoization into the connect methods would be really helpful. This probably means the connect methods need to become hooks in React.