Comparing initialValues from enableReinitialize and values in onSubmit

I have a form that uses `enableReinitialize` to hydrate my `initialValues` from an api call. I have a use case where I want/need to compare `initialValues` and `values` in `onSubmit` to determine what values to send in a request. I don't want to send values that don't differ from what's in `initialValues`.

` {
console.log("values in onSubmit", values);

// initialValues is undefined below
const { initialValues } = props;

alert(JSON.stringify(values, null, 2));
try {
// compare initialValues and values
setLoggingFacilities(values.facilities);
const valuesToSend = values.facilities
.filter((facility, i) => {
// Let's send only those that have just been disabled or enabled:
return (
facility &&
initialValues[i] &&
facility.enabled !== initialValues[i].enabled
);
})
.map(facility => ({
key: facility.facilityName,
value: facility.enabled
}));
} catch (error) {
console.log("error catch", error);
}`

Haven't had much feedback asking this question in various other places.
I have a [codesanbox here](https://codesandbox.io/s/logging-table-l2rut)

Start with the enableReinitialize and onSubmit behavior described in the issue, then reproduce the case in the linked CodeSandbox. Determine whether the reported undefined initialValues is expected or a bug, and define done as a documented or tested way to compare the reinitialized values with submitted values.

Written by the indexing model from the issue text.