chore: import upstream snapshot with attribution

cpp/example/example.cc

@@ -0,0 +1,59 @@
+/// This is an example of Ray C++ application. Please visit
+/// `https://docs.ray.io/en/master/ray-core/walkthrough.html#installation`
+/// for more details.
+
+/// including the `<ray/api.h>` header
+#include <ray/api.h>
+
+/// common function
+int Plus(int x, int y) { return x + y; }
+/// Declare remote function
+RAY_REMOTE(Plus);
+
+/// class
+class Counter {
+ public:
+  int count;
+
+  Counter(int init) { count = init; }
+  /// static factory method
+  static Counter *FactoryCreate(int init) { return new Counter(init); }
+
+  /// non static function
+  int Add(int x) {
+    count += x;
+    return count;
+  }
+};
+/// Declare remote function
+RAY_REMOTE(Counter::FactoryCreate, &Counter::Add);
+
+int main(int argc, char **argv) {
+  /// initialization
+  ray::Init();
+
+  /// put and get object
+  auto object = ray::Put(100);
+  auto put_get_result = *(ray::Get(object));
+  std::cout << "put_get_result = " << put_get_result << std::endl;
+
+  /// common task
+  auto task_object = ray::Task(Plus).Remote(1, 2);
+  int task_result = *(ray::Get(task_object));
+  std::cout << "task_result = " << task_result << std::endl;
+
+  /// actor
+  ray::ActorHandle<Counter> actor = ray::Actor(Counter::FactoryCreate).Remote(0);
+  /// actor task
+  auto actor_object = actor.Task(&Counter::Add).Remote(3);
+  int actor_task_result = *(ray::Get(actor_object));
+  std::cout << "actor_task_result = " << actor_task_result << std::endl;
+  /// actor task with reference argument
+  auto actor_object2 = actor.Task(&Counter::Add).Remote(task_object);
+  int actor_task_result2 = *(ray::Get(actor_object2));
+  std::cout << "actor_task_result2 = " << actor_task_result2 << std::endl;
+
+  /// shutdown
+  ray::Shutdown();
+  return 0;
+}