Describe the bug
World load times are increased by 100x when Flans is installed with the official content packs.
This is to do with the way that your handling player class starter items.

Perhaps a better way would be to do this only for overworlds loading, or even better during/post server startup.

Its worth noting that forge hotloads dimensions on 1.12 to improve performance with mods that create multiple dimensions, so you're locking the server thread for a few seconds every time a player swaps between them.

This issue can be mitigated by increasing I:dimensionUnloadQueueDelay in config/forge.cfg, but this effectively keeps the extra dimension loaded to avoid having to load it again, which defeats the purpose of the function in forge in the first place.

To Reproduce
Steps to reproduce the behaviour:

1. Install Flansmod
2. Install a multiworld mod, like Advanced Rocketry or JED.
3. Swap dimensions - measuring the time it takes.

Expected behaviour
Worlds should load in less than 100ms.

Screenshots
N/A

Versions (please complete the following information)

• Forge: Latest 1.12
• Flan's Mod: 5.6.0 (Occurs on 5.5.2 too)

Additional context
N/A