$ build-support/bin/check_rust_formatting.sh
info: using existing install for '1.21.0-x86_64-apple-darwin'
info: override toolchain for '/Users/stuhood/src/pants' set to '1.21.0-x86_64-apple-darwin'

  1.21.0-x86_64-apple-darwin unchanged - rustc 1.21.0 (3b72af97e 2017-10-09)

[Waiting for /Users/stuhood/.cache/pants/rust/cargo/bin/cargo fetch --manifest-path /Users/stuhood/src/pants/src/rust/engine/Cargo.toml (pid 49386) to complete]