Class Queue

plugins/experimental/wasm/lib/src/shared_queue.h:37–42

private:
  struct Queue {
    std::string vm_key;
    uint32_t context_id;
    CallOnThreadFunction call_on_thread;
    std::deque<std::string> queue;
  };

  // TODO: use std::shared_mutex in C++17.
  std::mutex mutex_;