Converting number primitives (i32, f64, etc) to byte representations

As of Rust 1.32 you can use {to,from}_{ne,le,be}_bytes for integral types.

let begin = 1234_i32;
let bytes = begin.to_ne_bytes();
let and_back = i32::from_ne_bytes(bytes);

For floating point you still have to rely on prior methods.