[1.15.2] Rendersystem called from wrong thread

[Elsopeen]

Hello,

I'd like to have a special armor that allows player to throw a force field when right click but only when they wear the complete armor set.

Here's the repo of the project, and here's the crash report.

I know that we should use an event based method rather than checking with ticks, but I have no idea what function I should create/call to do that.

I don't even understand why this kind of method could provoque such error.

So please, I hope you could help me on this one,

Thanks anyway,

Elsopéen