public Object getUndoRedoState(DomainObject domainObject) {
		// do nothing by default; subclasses should override as needed
		return null;
	}
Returns an object containing the plugin's state as needed to restore itself after an undo
or redo operation.  Plugins should override this method if they have special undo/redo handling.
@param domainObject the object that is about to or has had undoable changes made to it.
@return the state object
Ghidra/Framework/Project/src/main/java/ghidra/framework/plugintool/Plugin.java