import * as React from 'react'; import { Tabs, TabItem } from '@fluentui/react-tabs'; import { Toggle } from '@fluentui/react/lib/Toggle'; import { useBoolean } from '@fluentui/react-hooks'; const ExpensiveToMount: React.FC = () => { const [mounted, setMounted] = React.useState(false); React.useEffect(() => { setTimeout(() => { setMounted(true); }, 3000); }, []); return