There is no way to pre-generate all the lighting data on an existing world / --forceUpgrade doesn't fully upgrade

In the changelog for 1.14.2-pre4 the following is stated:

• All light will now be re-calculated the first time you open a world saved in a pervious version [sic]

This calculation seems to take some time for each chunk, leading to significant lag when a new chunk is loaded. I experienced severe rubber-banding and errors in my log. After the chunks have been re-calculated, the game plays perfectly fine (much, much better than the current 1.14.1 release)

It would by nice if server owners could properly pre-calculate light for the entire world before making the switch to 1.14.2, in the same way we could for 1.13 with the `--forceUpgrade` flag.

For the inevitable comments: I have tried with {{--forceUpgrade --eraseCache }}flags, and the lag still occurs.