rustc-ap-serialize 509.0.0

Automatically published version of the package `serialize` in the rust-lang/rust repository from commit bdd4bda4d5fe7eb24a7209a6c0c968a54869d3b7 The publishing script for this crate lives at: https://github.com/alexcrichton/rustc-auto-publish

Support code for encoding and decoding types.