Basic geometry classes for Cesium.
@ SUBTREE_LOADED
This tile has a subtree that is loaded.
@ REACHABLE
The tile is reachable through the tileset availability tree.
@ SUBTREE_AVAILABLE
This tile has a subtree that is known to be available.
@ TILE_AVAILABLE
The tile is known to be available.
@ CONTENT_AVAILABLE
The tile's content is known to be available.