This branch/commit is only useful to those who purely use a clean Bukkit/Spigot/Paper API
and does not use NMS/OBC references.
This will let you start updating your plugin to the latest 1.13 builds of Bukkit Preview (4 as of now)
Note that this release is not final!!! API breakages may occur!
It is up to you if you find use out of this work.
Importing the full library would double the jar size... its way too large.
So lets just import the basic int/long based collections to then use
to improve performance on these kind of collections.
Aikar
Zach Brown