Changing field value from side effects

### A **feature request**

To change a field's value from a side effect thread being it redux-saga or redux-observable.

### What is the current behavior?

As I'm concerned there's no elegant way to update a field's value as a part of the side effect.

### What is the expected behavior?

I want to be able to change the value of a field as a reaction to some event in the environment. Essentially in some cases changing a field's value is a part of a side effect.