I'd like to achieve this:
https://jsfiddle.net/cmyker/ooxdL2vj/
But haven't found a way to register a plugin.
Never mind. I noticed later that this._chart is available only after rendering and that Chart is global.
Sadly Chart.js is kind of limited if you want to work with the labels and positions of text.
It is a highly requested feature to render the labels inside a doughnut or have connected lines between the chart and the open label.
There is also ECharts which seem to have more features in this directions.
@rzb Can you elaborate on your solution please?
If someone still search for:
https://gist.github.com/chhumsina/9bcc54851d19123d4a849432696f4bda
Most helpful comment
If someone still search for:

https://gist.github.com/chhumsina/9bcc54851d19123d4a849432696f4bda