fix: Fix incorrect data size handling in struct layout Update mod.rs

[brawncode]

An issue with the struct layout where Size and Data were incorrectly assumed to have fixed sizes. Specifically, Size was defined as u32 (4 bytes), followed by Data (incorrectly assumed to always be 4 bytes), and then C (CRC32, 4 bytes). This doesn't align with the actual requirements since Data can have a variable length. I've updated the implementation to correctly handle Data as a variable-length field, ensuring the struct layout matches the intended design. This should resolve any inconsistencies in memory alignment and data parsing.

[patrick-ogrady]

I think this is a fair suggestion. Would you mind indicating below C = CRC32(Data) what N is?

Wonder if it would be clear to just call it D (for Data) and do D+4, D+5, D+6, D+7 for size (incorporating values from before)

[brawncode]

Here, N is a variable representing a starting index from which the numbering continues as N, N+1, N+2, N+3.

Yes, we can absolutely name the variable D instead of N. The choice of variable name is arbitrary and depends on the context or the developer's preference. The name N is often used to represent a generic number or index, but D could also be a valid choice, especially if it aligns better with the meaning or purpose of the variable in your code.