@Override
						public void run() {
							tree.collapseAll(tree.getViewRoot());
						}
Subclass must implement this method to generate their children. This operation will always be
performed in a background thread (i.e. Not the swing thread)

@param monitor a TaskMonitor for reporting progress and cancel notification.
@return the list of children for this node.
@throws CancelledException if the monitor is cancelled
Ghidra/Framework/Docking/src/main/java/docking/widgets/tree/GTreeSlowLoadingNode.java