Current non-server-friendly workaround

Entities.java

package kvverti.enim.entity;

/* imports... */

/** Utility class for working with Entitys and TileEntitys. */
public final class Entities {

	/* methods... */

	public static class TickEventHandler {

		public static final TickEventHandler INSTANCE = new TickEventHandler();
		private static final WeakHashMap<Entity, IntCounter> entityCounters = new WeakHashMap<>();
		private static final WeakHashMap<TileEntity, IntCounter> tileCounters = new WeakHashMap<>();
		private static final WeakHashMap<Entity, IntCounter> jumpCounters = new WeakHashMap<>();

		private byte slow = 0;

		private TickEventHandler() { }

		@SubscribeEvent //Increment every world tick. Event is sent only by the server :(
		public void onWorldTick(WorldTickEvent event) {

			if(event.phase == Phase.START && ++slow % 3 == 0) {

				entityCounters.values().forEach(IntCounter::preIncrement);
				tileCounters.values().forEach(IntCounter::preIncrement);
				jumpCounters.values().stream()
					.filter(counter -> counter.get() >= 0)
					.forEach(IntCounter::preIncrement);
			}
		}

		@SubscribeEvent //Event is sent only by the server :(
		public void onLivingJump(LivingJumpEvent event) {

			jumpCounters.computeIfAbsent(event.entityLiving, e -> new IntCounter()).reset();
		}

		/* getters, etc... */
	}
}