we can safely assume this for blocks (though the type info doesn't reflect it) but this is not safe to assume for random APIs that might be used by plugins.
Farmland can end up scanning up to 162 blocks looking for water in the worst case. This is obviously not great for huge farms where there are thousands of blocks of the stuff.
In most farms, the water won't be moved, and nor will the farmland. This means that we can avoid this costly search on random updates.
This PR implements a cache using blockstate data (only possible in PM5) which stores an index mapping to a coordinate offset where water was previously found by this farmland block. This allows the farmland to avoid water searching entirely in most cases.
This is a colossal improvement as compared to scanning the whole 9x2x9 area every time, which, on average, scans about 40 blocks to find water if the water is at the same Y coordinate. In real terms this translates into about a 8x performance improvement for farmland (see timings below).
xxhash is generally well known for its hash key properties, so this is a suitable use case.
We XOR the state data with a partial hash of xxh3(typeID), which provides sufficient hash distribution regardless of the size of state data.
The previous method started to break down as the number of bits exceeded the number of significant bits of type ID (about 10 currently).
As well as being better for hash distribution regardless of state data size, this also reduces the load factor of RuntimeBlockRegistry to 1.08 (previously around 1.24), which is a nice bonus.
until now, any thread crash would show as a generic crash since we aren't able to get the trace from the crashed thread directly. This uses some dirty tricks to export a partially serialized stack trace to the main thread, where it can be written into a crashdump.
This enables us to see proper crash information for async tasks in the crash archive (finally!!!) as well as being able to capture RakLib errors properly.
