How can I improve performance on a huge string?

[YueYongDev]

when i use this plugin for parse a huge json string, the page run very slow, so how can i improve performance?

[cekrozl1]

Using a performance run you can see that it's coming from "Paint" which means that the widget is hard to render.
You can also see that using a simple Text Widget instead of JsonView doesn't create Jank: