Lags when expand row with many childs

[EarlOld]

https://codesandbox.io/s/tender-clarke-iq2pk?file=/src/App.js - Example

Steps: Create table Add to row many children Click to expand icon

Delay in 5s in sandbox, in my app with custom render function - 10s

All application does not work in 5s. Can we fix it? Maybe can add some loader icon when data rendering

[vladpuz]

Possibly a duplicate https://github.com/react-component/table/issues/235