runAtEntityLater method broken on Paper only

[PikaMug]

Thank you for adding c720ba1 it works great on Folia!

However, it seems to have broken on Paper, with or without a fallback parameter. FoliaLib 0.3.3 executes the consumer, whereas 0.3.4 simply does not. Furthermore, if a fallback runnable is specified, that gets triggered instead (tested with ProjectileLaunchEvent where the fallback is triggered immediately on launching a Fireball via Player#launchProjectile).

Edit: It appears the Projectile#isValid check returns false on Paper? Perhaps #isDead would be preferable?

Java 17 with Paper version git-Paper-370 (MC: 1.20.4) (Implementing API version 1.20.4-R0.1-SNAPSHOT) (Git: 1fa48d1)

[Browsit]

We get a repeating StackOverflowError when spawning a custom mob which may be caused by this (did not occur on 0.3.3):

[17:35:53 ERROR]: Could not pass event MythicMobSpawnEvent to TestPlugin v1.0
java.lang.StackOverflowError: null
        at org.bukkit.craftbukkit.v1_20_R3.entity.CraftEntity.isValid(CraftEntity.java:389) ~[paper-1.20.4.jar:git-Paper-477]
        at org.browsit.testplugin.libs.folialib.impl.SpigotImplementation.runAtEntityLater(SpigotImplementation.java:236) ~[TestPlugin-1.0-SNAPSHOT.jar:?]

[TechnicallyCoded]

I'm currently away for vacation, sorry for the slow replies. I'll do my best to address this asap. If anyone wants to PR a fix in the meantime, feel free :)