How to turn on asynchronous rendering of react fidber

look at http://isfiberreadyyet.com/. fidber is already available. Now I"d like to try asynchronous rendering mode.

The

page uses https://unpkg.com/react@16.5., searches the source code, and sees
clipboard.png

the latest Google, hasSymbol uses a large page for true,. It takes a long time to render for the first time, but when you drag the scroll bar, you still can"t respond in time. It will stutter. How can you be sure whether asynchronous rendering is enabled?

Aug.21,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b42f77-2c66f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b42f77-2c66f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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