mmap dependency

[s3bk]

Wasm32 does not support mmap, but epserde would still be nice to have there.

I am working on a PR to make the mmap dependency optional.

[s3bk]

Okay, I thought I was dumb, but the mem_dbg' had the mmap` feature enabled all the time.

[zommiommy]

Yeah, if you don't want mmap, we have to put behind cfg gates MemCase and some other structs. It should be doable.

[s3bk]

Yep. Working on it.

[s3bk]

Thank you for the crate!
I was looking for something less complicated than rkyv, but still zero-copy for most of the data.

[vigna]

BTW, please tell us if you find anything less than clear in the docs. We're deep inside of it so we can't really see where we are giving something for granted.