Hangs when loading large directories since 3.34

I think nautilus has started doing some synchronous I/O when loading directories, since 3.34.

Try navigating to /usr/lib64 in nautilus 3.34.0. You will lose control of nautilus and have to kill it to reopen. The process hasn't completely hung -- if I Alt+Tab, I can see every 5-10s or so it gains or loses window focus, and if I scroll it will scroll a little bit 5-10s later -- but it's clearly nonresponsive for long periods of time.

3.32 was fine.