boolean isBusy() {
		synchronized (addRemoveUpdater) {
			return thread != null || pendingJob != null || addRemoveUpdater.isBusy() ||
				!addRemoveWaitList.isEmpty();
		}
	}
Returns true if there is any scheduled work that has not been completed, including any
deferred add/removes. 
@return true if there is work to be done.
Ghidra/Framework/Docking/src/main/java/docking/widgets/table/threaded/ThreadedTableModelUpdateMgr.java