double-checked-cell 2.0.1

A thread-safe lazily initialized cell using double-checked locking
sudo: false
language: rust
addons:
  apt:
    packages:
     - libcurl4-openssl-dev
     - libelf-dev
     - libdw-dev
rust:
 - 1.27.0
 - stable
 - beta
 - nightly
before_script:
 - pip install 'travis-cargo<0.2' --user
 - export PATH=$HOME/.local/bin:$PATH
 - export TRAVIS_CARGO_NIGHTLY_FEATURE=
script:
 - travis-cargo test
 - travis-cargo test -- --features parking_lot_mutex
 - travis-cargo --only nightly test -- --features const_fn