language: rustsudo: falsematrix:  include:    - rust: stable    - rust: nightlyscript:    - cargo build    - cargo test    - cargo test --features serde    - |      if [ "$TRAVIS_RUST_VERSION" == "nightly" ]; then        cargo test --no-default-features        cargo test --no-default-features --features serde;      fi    - cargo doc --no-depsafter_success: |    if [ "$TRAVIS_RUST_VERSION" == "nightly" ]; then      cargo bench;    fi