add celery example

examples/celery/src/task_app/tasks.py

@@ -0,0 +1,23 @@
+import time
+
+from celery import shared_task
+from celery import Task
+
+
+@shared_task(ignore_result=False)
+def add(a: int, b: int) -> int:
+    return a + b
+
+
+@shared_task()
+def block() -> None:
+    time.sleep(5)
+
+
+@shared_task(bind=True, ignore_result=False)
+def process(self: Task, total: int) -> object:
+    for i in range(total):
+        self.update_state(state="PROGRESS", meta={"current": i + 1, "total": total})
+        time.sleep(1)
+
+    return {"current": total, "total": total}