if (world != null) {
Extent extent;
// This extents are ALWAYS used
extent = fastModeExtent = new FastModeExtent(world, false);
extent = survivalExtent = new SurvivalModeExtent(extent, world);
extent = quirkExtent = new BlockQuirkExtent(extent, world);
extent = chunkLoadingExtent = new ChunkLoadingExtent(extent, world);
extent = cacheExtent = new LastAccessExtentCache(extent);
extent = wrapExtent(extent, eventBus, event, Stage.BEFORE_CHANGE);