Using an unbound LinkedBlockingQueue means you *have* to set core and max core thread pool size the same, as they will never go above the minimum pool size by just passing them through. So this fixes the async command executor pool to actually use 2 threads, and also cleans up other usage to be explicitly "fixed" thread pool sizes, and splits off one more in Minecraft's Util class
This patch does not appear to be doing anything useful, and may
hide errors.
Currently, the save logic does not run through this path either
so it did not do anything.
Additionally, properly implement support for handling
RegionFileSizeException in Moonrise.
Firstly, the old methods all routed to the CompletableFuture method.
However, the CF method could not guarantee that if the caller
was off-main that the future would be "completed" on-main. Since
the callback methods used the CF one, this meant that the callback
methods did not guarantee that the callbacks were to be called on
the main thread.
Now, all methods route to getChunkAtAsync(x, z, gen, urgent, cb)
so that the methods with the callback are guaranteed to invoke
the callback on the main thread. The CF behavior remains unchanged;
it may still appear to complete on main if invoked off-main.
Secondly, remove the scheduleOnMain invocation in the async
chunk completion. This unnecessarily delays the callback
by 1 tick.
Thirdly, add getChunksAtAsync(minX, minZ, maxX, maxZ, ...) which
will load chunks within an area. This method is provided as a helper
as keeping all chunks loaded within an area can be complicated to
implement for plugins (due to the lacking ticket API), and is
already implemented internally anyways.
Fourthly, remove the ticket addition that occured with getChunkAt
and getChunkAtAsync. The ticket addition may delay the unloading
of the chunk unnecessarily. It also fixes a very rare timing bug
where the future/callback would be completed after the chunk
unloads.
