tree b1ce726aec8110d6e3aa2ec4f08159de2d74e9bd
parent 122ea7ee276626cdec2aca2c260d230c0621ae72
author Jiang Yan Xu <yan@jxu.me> 1434046060 -0700
committer Jiang Yan Xu <yan@jxu.me> 1434496085 -0700

Make sure task_runner.stop() is idempotent (clean up only once).