Server shutdown takes ages

[MastoryMd5]

Describe the bug
On server shutdown the server hands saving chunks, in certain cases it took 20+ minutes to save the world, cpu usage is high.

To Reproduce
Shutdown the server

Expected behavior
Shutdown should not take that much time.

Screenshots
Cpu usage during shutdown

Runtime info (please complete the following information):

• OS: Ubuntu 22.04.4, AMD Ryzen 9 9950X
• Minecraft version: 1.21.1 + Fabric Loader 0.16.10
• Mod version: c2me 0.3.0+alpha.0.314+1.21.1

Crash reports / logs
https://mclo.gs/VOAzqcY
(this continues for 10m)

Other mods
Mods: https://mclo.gs/KiL6UVp

Checklist

• I am using the official version of the mod.
• I tried the latest development version but the issue persists.
• I searched for similar open issues and could not find an existing bug report on this.

Additional context
Map should be around 60gb+, generally a /save-all doesn't take that much time so i'm wondering if there is some incompatibility issue with other mods or something else.

[ishland]

There might be mods trying to reload chunks during the shutdown process. Try getting the minimum set of mods reproducible.