Object getSynchronizingLock() {
		return addRemoveUpdater;
	}
Ensures that the result of this call is a cancellable monitor.

<P>If the monitor used by the jobs of this class is not cancellable, then the jobs cannot
properly move from state to state, since they are reused for new requests.
Ghidra/Framework/Docking/src/main/java/docking/widgets/table/threaded/ThreadedTableModelUpdateMgr.java