Feature Request - Total Count of Data in Pagination

I'm working with Grails JSON Views and discovered that it's not configurable in a few ways.

1. Count of the total rows of data cannot be enabled in jsonapi.render(). If I don't know the total count of the data, how can I construct my pagination view in pure html format such as this:

I can make another API call to specifically know the count of my rows of data. But if this can be enabled and be shown in the json output would be better.

```
{
data: [],
links: {},
total: '40'
}

```

Start with the jsonapi.render() pagination response and trace where its data and links fields are assembled. Confirm how pagination metadata is currently exposed, then define completion as returning a total field containing the total row count alongside the existing JSON output.

Written by the indexing model from the issue text.