240faf56a4
Implementations for ChunkStatuses below FULL are supposed to always return ProtoChunk instances. However, since we used the last completed status, it could return LevelChunk. To resolve this, follow Vanilla behavior of tracking chunk completions by status and replace old ProtoChunk statuses with ImposterProtoChunk when the chunk generates to FULL. Additionally, implement an optimisation for retrieving full chunks by storing a map of pos -> LevelChunk. This requires only a simple map lookup to occur for full chunks which are loaded.