Function fixed_size_diff 

pub fn fixed_size_diff<'a>(
    before: &'a [u8],
    after: &'a [u8],
    manifest: &'a LayoutManifest,
) -> Result<Vec<FieldDelta<'a>>, DiffError>

Compute a fixed-size diff (no resize). Returns a list of FieldDeltas . one per changed field.

Errors

• LengthMismatch if before.len() != after.len().
• BufferTooShort if either input is shorter than manifest.total_size.