this is now supported thanks to the object rescue feature implemented in pthreads 5.1, making returning of thread-safe values from async tasks possible.
This needs to be explicitly supported, since otherwise it will attempt to serialize them, which isn't supported anymore.
At the time when I wrote this code, I was still in the head space of the kind of ID hijacking that PM4 plugins do to override built-in blocks.
However, this kind of internal ID reuse makes no sense in PM5, since said IDs are only used in the core itself at runtime to identify types and states.
Even if we were to allow overriding block deserializers, overriding serializers makes no sense whatsoever, since the original block would continue to exist and be accessible.
There is a case to be made to allow overriding the deserializer, but not for the serializer.
this was previously part of the abandoned package pocketmine/spl. It had to be separated in the PM3 days, because RakLib depended on it.
Since RakLib 0.13, RakLib stopped being dependent on or aware of pthreads, so it no longer depends on any thread-related packages.
It's also possible to absorb pocketmine/snooze and pocketmine/classloader back into the core with this in mind.
Due to the high cost of Item::serializeCompoundTag(), it's very costly to rebuild this every time we need it. This is sent during the pre-spawn step, where we need to minimize costs as much as possible.
right now, I don't see an obvious reason to do this. If it turns out I was wrong later on, we can add functionality back, but we can't remove functionality after release.
due to the extremely large performance cost of instantiating AsyncTasks, it's usually not worth bothering with async compression except for very large packets.
While this large overhead can be significantly reduced by using specialized threads, it's early days in the testing stages for such improvements, and for now, we still have this to deal with.
Since async compression is always used prior to player spawn, this change may slightly improve the performance of the pre-join stage of the game.
we rely on phpstan for validation of this internally, and plugins shouldn't be calling these methods anyway.
this significantly reduces the overhead of CompressBatchPromise.
For blocks, we now use 'block-item state' and 'block-only state', which should be much clearer for people implementing custom stuff.
'block-item state', as the name suggests, sticks to the item when the block is acquired as an item.
'block-only state' applies only to the block and is discarded when the block is acquired as an item.
'type data' for items was also renamed, since 'type' is too ambiguous to be anything but super confusing.
