rustc-ap-serialize 261.0.0

Automatically published version of the package `serialize` in the rust-lang/rust repository from commit 2224a42c353636db6ee53cc3f9b1a968e9d9c1f6 The publishing script for this crate lives at: https://github.com/alexcrichton/rustc-auto-publish

Support code for encoding and decoding types.