High RAM usage when 10,000 entities are loaded. #441

Description

Feather uses way too much RAM for handling entities. When spawning 10 000 piglin brutes 1 in between each other, game uses 2 GB+ RAM and usage changes rapidly. RAM spike only happens when you are connected to the server.

Reproduction Steps

1. Modify query_entities plugin so that piglin brutes spawn every 1 block instead of every 12 blocks.
2. Add modified query_entities plugin
3. Launch feather server
4. Login to feather server and see RAM go up A LOT

What You Expected to Happen

I expected maybe increased CPU usage when joining server with a lot of entities and I also expected RAM to go up slightly because of loaded chunks.

What Actually Happened

After I joined the server CPU usage went up by 20% and RAM usage went up by ~2 GB and fluctuated uncontrollably (by about ~400 MB every second).

Screenshots and Logs

Your Environment

• Operating System: Windows 10
• Operating System Version: 21H1
• Feather Version: latest

Additional Context

System RAM: 8 GB
Minecraft client: Lunar
View distance: 8 chunks (but Lunar tends to load chunks more slowly to maintain good FPS)

When no one is on the server, CPU usage stays around ~20% and RAM usage is ~6 MB.
Also when I joined server, my CPU reached 100% and server printed Tick took too long once in a while and my RAM stayed around ~95% usage.