FixedSizeBlock::interpret should either check alignment or use read_unaligned

[afranchuk]

read is used here:

zip2/src/spec.rs

Line 112 in ad111aa

let block = unsafe { block_ptr.read() }.from_le();

However the alignment hasn't been verified prior to this. It so happens that FixedSizeBlock is (currently) only implemented on repr(packed) structs (which have 1-byte alignment), however the alignment should still be verified or read_unaligned should be used.

If these should always be repr(packed), maybe add an assert_eq!(std::mem::align_of::<Self>(), 1)?

[afranchuk]

The same can be said for

zip2/src/spec.rs

Line 141 in ad111aa

out_ptr.write(self);