`CommandBuffer` for purely unmanaged structs

[genaray]

The current CommandBuffer works for classes and structs of all kinds. However an additional unmanaged version for only unmanaged structs could potentially be faster and use less memory. From experience, only mostly unmanaged entities or components are recorded anyway.

This should be researched.

Idea

Nothing would change in the API. The way in which the CommandBuffer records the commands would only change internally. The only problem... managed structs and classes would no longer be supported.