this produced a 40% performance improvement in a simulation with 800 item entities.
If the items were all different, then this would still be a problem. However, many of the same unstackable items occupying the same space is a problem for SkyBlock farms, so this should improve performance for SkyBlock quite a bit.
fixes#5810
probably fixes#4986#5810 was caused by the workaround for #4394, which broke in 1.20 for reasons I'm still unclear on.
As FLAG_TELEPORT does not work at all for non-player entities, and causes bugs with player entities, sending the teleport movement without the flag is the least buggy way to solve all of these issues. Having the client interpolate teleport movements is not ideal, but there doesn't seem to be a way to reliably prevent it without causing even more bugs, so this will have to do.
closes#5645
the code for this is borrowed from ItemEntity. I didn't feel like a base class was appropriate, and we can't (yet) declare constants in traits.
since item merging is a potential hotspot, we want to know if this code section is a performance problem.
Current timers only tell us whether overall ticking of a particular entity is slow, but that includes movement and therefore isn't particularly helpful.
This allows plugins to modify the entity via setters in EntitySpawnEvent without their changes getting overwritten by setter calls directly after the 'new YourEntity' statement.
As well as benefiting plugins, this also clears a path for a BC-breaking change in PM5 (to have the programmer use addEntity() to spawn entities, instead of the constructor doing it, which will improve on a number of data handling aspects).
fixes#4973
This targets next-minor because it has some side effects on plugins that depended on the old behaviour, such as VanillaHopper, so it's not suitable for a patch release.
