CesiumJS in React Cause Memory Leak

1. A concise explanation of the problem you're experiencing.
I used CesiumJS in a React project and created a React component that contains a rotating Earth.When I left this subpage (eg returning to the homepage), this component was unmounted, but I found that there was always memory not freed, especially those occupied by the GPU process (the "Task Manager" in Chrome).

If I enter this page multiple times, the memory occupied by the GPU process will increase accordingly unless I refresh the entire page.

I also tried on other browsers(IE 11/Firefox)and encountered similar problem, with different severity. The memory will increase everytime I enter that page.

2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.
Main code as below:

You should try calling this.viewer.destroy() in your component’s componentWillUnmount() lifecycle method to clean up the Cesium instance when the component is removed.

I have already called it.

BTW, code here: https://github.com/Evelynzzz/CesiumDemo

Hi there,

This may have to do with Issue #5462. I’ll bump the issue with this report.