Yuncheng Li, @raoqiyu, Robert DiPietro, Sam Abrahams, Sebastian Raschka,
Siddharth Agrawal, @snakecharmer1024, Stephen Roller, Sung Kim, SunYeop Lee,
Thijs Vogels, Till Hoffmann, Victor Melo, Ville Kallioniemi, Waleed Abdulla,
Wenjian Huang, Yaroslav Bulatov, Yeison Rodriguez, Yuan Tang, Yuxin Wu,
@zhongzyd, Ziming Dong, Zohar Jackson

We are also grateful to all who filed issues or helped resolve them, asked and

      TF_EXCLUSIVE_LOCKS_REQUIRED(execution_mutex_);

  enum class ExecutionState {
    kReadyToExecute,
    kHasResult,
    kIdle,
    kShuttingDown,
  };

  tensorflow::mutex execution_mutex_;
  ExecutionState execution_state_ TF_GUARDED_BY(execution_mutex_) =
      ExecutionState::kIdle;
  // Tells the worker thread that there is new work.
  tensorflow::condition_variable start_execute_;