this is the synchronous forced version of shutdown - it will get called in the case of the octree server being shutdown. This is typically going to happen if the domain shuts down or if the voxel-server node was killed on the domain server status page. In this case, we can block the main thread since the domain server is already ignoring checkins from this node so blocking is ok.

We want to block, because we really want to make sure this node is shutdown and all of it's resources are freed.