Ixeris

This version resolved rare crashes, improved stability and also performance.

• Many awesome thread safety and scheduling strategy improvements, courtesy of @LitnhJacuzzi. These changes bring improved stability and a decent FPS boost.
• Added 1.19.4 support (courtesy of LitnhJacuzzi)
• Refactored the callback threading system to be simpler yet more reliable
• Fixed slow memory leak when setting callbacks