The Player View Distance patch has been screwing with the configured world view distance.
The world a player was created in would set the players view distance, which would be locked to that distance.
Then switching worlds would not give you an updated view distance.
This then caused issues with what view distance the player should have in the chunk map and did not send chunks to the client correctly during movement.
This patch has now been changed to use a -1 default for "default" and will not override view distance until someone has actually used the API to change it.
Allowing only non-zero BlockIterators breaks an API contract explicitly allowing them
(*eyeroll*)
And loading chunks earlier in the TP patch did not resolve the original issue, and now
that it is resolved, shouldn't actually provide any tangible benefits
By default, this logic would loop endlessly trying to fill the world
with entities until it hits the worlds spawn.
This patch will cap the # of attempts to so that the tick does not spend
extra long time on mob spawning
If a plugin hacks into NMS and triggers entity removal, it could
result in an entity being attempted to remove from the chunk twice.
The 2nd pass will return false, as it did not find the entity in the list.
We should not touch entity counts if the entity was not removed, to avoid
going negative.
Spigot drastically altered vanilla mob spawn logic and caused a few issues.
1) Used only spawnable chunks vs entire world for entity counting, resulting in ignoring
other entities in the world, and causing the world to go over its intended limit.
Specially with servers using smaller mob spawn ranges than view distance, as well as affects spawning API
2) Spigot was using 16x16 division instead of vanilla 17x17 division.
Issues got worse in 1.9 due to more chunks being loaded due to 1.9 changes, that fall out
of the monster spawn radius.
This patch returns mob counting to use all loaded chunks, and 17x17 division.
