This method shows up as super hot in profiler, and also a high "self" time.
Upon analyzing, it appears most usages of this method fall down to the final
else statement of the nasty ternary.
Upon even further analyzation, it appears then the majority of those have a
consistent list 1.... One with Infinity head and Tails.
First optimization is to detect these infinite states and immediately return that
VoxelShapeMergerList so we can avoid testing the rest for most cases.
Break the method into 2 to help the JVM promote inlining of this fast path.
Then it was also noticed that VoxelShapeMergerList constructor is also a hotspot
with a high self time...
Well, knowing that in most cases our list 1 is actualy the same value, it allows
us to know that with an infinite list1, the result on the merger is essentially
list2 as the final values.
This let us analyze the 2 potential states (Infinite with 2 sources or 4 sources)
and compute a deterministic result for the MergerList values.
Additionally, this lets us avoid even allocating new objects for this too, further
reducing memory usage.
Spottedleaf
Aikar