[1.14] Freezes when calling World.getChunk() during chunk loading

[felinoid]

I'm trying to update my mod to 1.14, and I'm having trouble with the part where I replace Minecraft horses with my custom horses. I subscribe to OnEntityJoinWorld events, but when I try to spawn my custom horse in response, the game never loads the chunk. If it happens in the loading screen the game freezes at 100%, or if it happens when a chunk is generated as part of exploration the chunk never loads. My event subscribed code seems to be getting stuck on World.getChunk called from within EntityType.spawn, presumably because it's getting called when the chunk isn't fully loaded yet. Is there a way around this?

[felinoid]

https://github.com/tiffanyjager/horse-colors/blob/master/src/main/java/horse_colors/HorseReplacer.java

 

The problem still happens when replaceHorses is reduced to

    @SubscribeEvent
    public static void replaceHorses(EntityJoinWorldEvent event)
    {
        // We don't want to replace subclasses of horses
        if (event.getEntity().getClass() == HorseEntity.class
            && !event.getWorld().isRemote)
        {
            HorseEntity horse = (HorseEntity)event.getEntity();
            HorseGeneticEntity newHorse = ModEntities.HORSE_GENETIC.spawn(event.getWorld(), null, null, null, new BlockPos(horse), SpawnReason.CONVERSION, false, false);
        }
    }

 

[felinoid]

Ok, how do I tell when the chunk is loaded?