Ability to put value inside Donut (Pie) chart

<!-- Please only use this template for submitting feature requests --> **Why is this needed**: The Donut chart is a variation of the Pie chart, that does not seem to provide as much value as it could. **What would you like to be added**: Currently I can create a Donut chart that looks like this:  What I would like is the ability to do this:  I would like the option to display the **total** number of values in the center of the graph. The edges could optionally still show labels, or only show on hover. **Who is this feature for?** This graph shows websocket connections from my application to external relays in a decentralized social network. It is broken up into connections that are in "open", "connecting", "closing", and "closed" state (the websocket readyState). I want to be able to quickly glance to see the _total_ number of connections, and then be able to see the proportion that are open, closed, etc.