enabling FileVault2 on APFS appears to be instant (no progress for encrypting drive)
In the past (before APFS) I remember that enabling FileVault would take several hours, during which time it said "Encrypting..." with a percentage progress counter in Settings -> Security & Privacy.
So I was surprised just now when I enabled FileVault2 on APFS on macOS Mojave 10.14.5 on a MacBook Air 2018, and it instantly went to "FileVault is turned on for the disk". I even tried to turn it off again, which was instant too. When I then turned it on again, it was also instantly turned on.
How is it possible that this is so fast?
I ran this command:
fdesetup status
which results in:
FileVault is On.
I also ran this command:
diskutil apfs list
and it displays this for the main volume, so it appears to be
+-> Volume disk1s1 [...]
| ---------------------------------------------------
| APFS Volume Disk (Role): disk1s1 (No specific role)
| Name: Macintosh HD (Case-insensitive)
| Mount Point: /
| Capacity Consumed: 37444063232 B (37.4 GB)
| FileVault: Yes (Unlocked)
MacBook Air 13", macOS 10.14