this.chunkManager.close();
this.chunkManager = null;
// close all loaded regions, saving modified images.
// this will create extra tasks that need to be completed.
this.executor.addTask(new CloseRegionManagerTask(this.regionManager));
this.regionManager = null;
MwUtil.log("waiting for %d tasks to finish...", this.executor.tasksRemaining());
if (this.executor.close()) {
MwUtil.log("error: timeout waiting for tasks to finish");