code: public void handleEvent(final BitfinexStreamSymbol symbol) {
  		final List<FutureOperation> futuresToFinish = pendingFutures
  				.stream()
  				.filter(f -> f.getSymbol().equals(symbol))
  				.collect(Collectors.toList());
  		
  		pendingFutures.removeAll(futuresToFinish);
  		
  		futuresToFinish.forEach(f -> f.setToDone());
  	}
docs: Handle a subscribe or unsubscribe event