ChunkDataEvent.Load is fired when vanilla Minecraft attempts to load Chunk data.
This event is fired during chunk loading in
{@link net.minecraft.world.chunk.storage.ChunkSerializer.read(ServerWorld, TemplateManager, PointOfInterestManager, ChunkPos, CompoundNBT)} which means it is async, so be careful.
ChunkDataEvent.Save is fired when vanilla Minecraft attempts to save Chunk data.
This event is fired during chunk saving in
AnvilChunkLoader#saveChunk(World, Chunk).