* this:
1. establishes provenance for the memory region in Rust, no "writing past the end of a 1 byte static"
2. establishes that the data is not mut but writes are allowed, no "const to mut" conversion, which would be UB
3. enforces the size is correct both in Rust and linker domains
4. enforces the initial value is not established, and the SAFETY comments of GroundedArrayCell says "it's on you to init before use".