Component to subscribe to specific field values

### Are you submitting a **bug report** or a **feature request**?

Feature request

To subscribe to more than one value I use the following pattern:

```

{({ input: fieldName1Input }) => (

{({ input: fieldName2Input }) => (

)}

)}

```

Obviously this is tedious. I would like to use a component similar to this instead:

```

{({ values }) => (

)}

```

Is there anything similar built in and I'm just unable to find it or is it a good idea?

Start by reviewing the existing Field component and subscription API, then compare them with the requested FieldValuesSpy usage. Done means the project has a supported way to subscribe to the listed field values and the behavior is covered by the relevant tests or documentation.

Written by the indexing model from the issue text.