LT_zone_ready

boolean LT_zone_ready(blockpos location)

Returns true if the zone containing a location is ready, that it can be modified. Before attempting to modify the world's blocks or props, you should check to see if the zone containing the location you're modifying is ready. If the zone is not ready, calls to modify the world there will be ignored. If you're modifying the world around the player in the middle of the game (not during loading or transitions), its generally safe to modify the world.