rustc-ap-serialize 340.0.0

Automatically published version of the package `serialize` in the rust-lang/rust repository from commit 729d3f07b4a6c558a7e86f1786a6905faddcfea8 The publishing script for this crate lives at: https://github.com/alexcrichton/rustc-auto-publish

Support code for encoding and decoding types.