code: public static BiFunction<Scheduler, ScheduledExecutorService, ScheduledExecutorService> removeExecutorServiceDecorator(String key) {
  		BiFunction<Scheduler, ScheduledExecutorService, ScheduledExecutorService> removed;
  		synchronized (DECORATORS) {
  			removed = DECORATORS.remove(key);
  		}
  		if (removed instanceof Disposable) {
  			((Disposable) removed).dispose();
  		}
  		return removed;
  	}
docs: Remove an existing {@link ScheduledExecutorService} decorator if it has been set up
  via {@link #addExecutorServiceDecorator(String, BiFunction)}. Note that the {@link Factory}'s
  legacy {@link Factory#decorateExecutorService(String, Supplier)} method is always
  applied last, even if all other decorators have been removed via this method.
  <p>
  In case the decorator implements {@link Disposable}, it is also
  {@link Disposable#dispose() disposed}.
  
  @param key the key for the executor service decorator to remove
  @return the removed decorator, or null if none was set for that key
  @see #addExecutorServiceDecorator(String, BiFunction)
  @see #setExecutorServiceDecorator(String, BiFunction)