docs: public <K, N> InternalTimerService<N> getInternalTimerService(
  			String name,
  			TypeSerializer<N> namespaceSerializer,
  			Triggerable<K, N> triggerable) {
  
  		checkTimerServiceInitialization();
  
  		// the following casting is to overcome type restrictions.
  		KeyedStateBackend<K> keyedStateBackend = getKeyedStateBackend();
  		TypeSerializer<K> keySerializer = keyedStateBackend.getKeySerializer();
  		InternalTimeServiceManager<K> keyedTimeServiceHandler = (InternalTimeServiceManager<K>) timeServiceManager;
  		TimerSerializer<K, N> timerSerializer = new TimerSerializer<>(keySerializer, namespaceSerializer);
  		return keyedTimeServiceHandler.getInternalTimerService(name, timerSerializer, triggerable);
  	}