feat: add attribute to @sync which always sends, and don't store a previous copy

[sekwah41]

This will be helpful for tracking info that is rapidly changing or is far more likely to always be different and isn't worth the checks. E.g. if you were using it for vr body tracking due to small constant changes it would almost always be different.

Might make sense more for custom objects to possibly flag that copies shouldn't be made and always send. Though probably want to avoid encouraging it.